Move DOM and config properties from the util namespace to the DOM and config namespaces, respectively.

19 files changed, 719 insertions, 594 deletions

diff --git a/common/content/bookmarks.js b/common/content/bookmarks.js
index 388b8f20..97c2eaad 100644
--- a/common/content/bookmarks.js
+++ b/common/content/bookmarks.js
@@ -116,13 +116,13 @@ var Bookmarks = Module("bookmarks", {
      */
     addSearchKeyword: function addSearchKeyword(elem) {
         if (elem instanceof HTMLFormElement || elem.form)
-            var [url, post, charset] = util.parseForm(elem);
+            var { url, postData, charset } = DOM(elem).formData;
         else
-            var [url, post, charset] = [elem.href || elem.src, null, elem.ownerDocument.characterSet];
+            var [url, postData, charset] = [elem.href || elem.src, null, elem.ownerDocument.characterSet];
 
         let options = { "-title": "Search " + elem.ownerDocument.title };
-        if (post != null)
-            options["-post"] = post;
+        if (postData != null)
+            options["-postData"] = postData;
         if (charset != null && charset !== "UTF-8")
             options["-charset"] = charset;
 
diff --git a/common/content/buffer.js b/common/content/buffer.js
index 3345a814..78dcd824 100644
--- a/common/content/buffer.js
+++ b/common/content/buffer.js
@@ -16,7 +16,6 @@
  */
 var Buffer = Module("buffer", {
     init: function init() {
-        this.evaluateXPath = util.evaluateXPath;
         this.pageInfo = {};
 
         this.addPageInfoSection("e", "Search Engines", function (verbose) {
@@ -24,8 +23,8 @@ var Buffer = Module("buffer", {
             let n = 1;
             let nEngines = 0;
             for (let { document: doc } in values(buffer.allFrames())) {
-                let engines = util.evaluateXPath(["link[@href and @rel='search' and @type='application/opensearchdescription+xml']"], doc);
-                nEngines += engines.snapshotLength;
+                let engines = DOM("link[href][rel=search][type='application/opensearchdescription+xml']", doc);
+                nEngines += engines.length;
 
                 if (verbose)
                     for (let link in engines)
@@ -79,7 +78,7 @@ var Buffer = Module("buffer", {
             for (let [i, win] in Iterator(buffer.allFrames())) {
                 let doc = win.document;
 
-                for (let link in util.evaluateXPath(["link[@href and (@rel='feed' or (@rel='alternate' and @type))]"], doc)) {
+                for (let link in DOM("link[href][rel=feed], link[href][rel=alternate][type]", doc)) {
                     let rel = link.rel.toLowerCase();
                     let feed = { title: link.title, href: link.href, type: link.type || "" };
                     if (isValidFeed(feed, doc.nodePrincipal, rel == "feed")) {
@@ -612,7 +611,7 @@ var Buffer = Module("buffer", {
             };
 
             DOM(elem).mousedown(params).mouseup(params);
-            if (!util.haveGecko("2b"))
+            if (!config.haveGecko("2b"))
                 DOM(elem).click(params);
 
             let sel = util.selectionController(win);
@@ -855,7 +854,7 @@ var Buffer = Module("buffer", {
         dactyl.assert(idx in elems);
 
         let elem = elems[idx][0];
-        elem.scrollIntoView(true);
+        DOM(elem).scrollIntoView();
 
         let sel = elem.ownerDocument.defaultView.getSelection();
         sel.removeAllRanges();
@@ -897,7 +896,7 @@ var Buffer = Module("buffer", {
         // focus next frame and scroll into view
         dactyl.focus(frames[next]);
         if (frames[next] != content)
-            frames[next].frameElement.scrollIntoView(false);
+            DOM(frames[next].frameElement).scrollIntoView();
 
         // add the frame indicator
         let doc = frames[next].document;
@@ -1207,7 +1206,7 @@ var Buffer = Module("buffer", {
             selection.removeAllRanges();
             selection.addRange(range);
         }
-        return util.domToString(range);
+        return DOM.stringify(range);
     },
 
     getDefaultNames: function getDefaultNames(node) {
@@ -1242,7 +1241,7 @@ var Buffer = Module("buffer", {
         names.push([decodeURIComponent(url.replace(/.*?([^\/]*)\/*$/, "$1")), "File Name"]);
 
         return names.filter(function ([leaf, title]) leaf)
-                    .map(function ([leaf, title]) [leaf.replace(util.OS.illegalCharacters, encodeURIComponent)
+                    .map(function ([leaf, title]) [leaf.replace(config.OS.illegalCharacters, encodeURIComponent)
                                                        .replace(re, ext), title]);
     },
 
@@ -1256,7 +1255,7 @@ var Buffer = Module("buffer", {
             pos = "scrollLeft", size = "clientWidth", max = "scrollWidth", layoutSize = "offsetWidth",
             overflow = "overflowX", border1 = "borderLeftWidth", border2 = "borderRightWidth";
 
-        let style = util.computedStyle(elem);
+        let style = DOM(elem).style;
         let borderSize = Math.round(parseFloat(style[border1]) + parseFloat(style[border2]));
         let realSize = elem[size];
         // Stupid Gecko eccentricities. May fail for quirks mode documents.
@@ -1288,7 +1287,7 @@ var Buffer = Module("buffer", {
         if (top != null)
             elem.scrollTop = top;
 
-        if (util.haveGecko("2.0") && !util.haveGecko("7.*"))
+        if (config.haveGecko("2.0") && !util.haveGecko("7.*"))
             elem.ownerDocument.defaultView
                 .QueryInterface(Ci.nsIInterfaceRequestor).getInterface(Ci.nsIDOMWindowUtils)
                 .redraw();
@@ -1307,7 +1306,7 @@ var Buffer = Module("buffer", {
      *   given direction.
      */
     scrollHorizontal: function scrollHorizontal(elem, unit, number) {
-        let fontSize = parseInt(util.computedStyle(elem).fontSize);
+        let fontSize = parseInt(DOM(elem).style.fontSize);
         let increment;
         if (unit == "columns")
             increment = fontSize; // Good enough, I suppose.
@@ -1337,7 +1336,7 @@ var Buffer = Module("buffer", {
      *   given direction.
      */
     scrollVertical: function scrollVertical(elem, unit, number) {
-        let fontSize = parseInt(util.computedStyle(elem).lineHeight);
+        let fontSize = parseInt(DOM(elem).style.lineHeight);
         let increment;
         if (unit == "lines")
             increment = fontSize;
@@ -1385,7 +1384,7 @@ var Buffer = Module("buffer", {
      *      column ordinal to scroll to.
      */
     scrollToPosition: function scrollToPosition(elem, horizontal, vertical) {
-        let style = util.computedStyle(elem);
+        let style = DOM(elem).style;
         Buffer.scrollTo(elem,
                         horizontal == null ? null :
                         horizontal == 0    ? 0    : this._exWidth(elem) * horizontal,
@@ -1399,7 +1398,7 @@ var Buffer = Module("buffer", {
      * @param {Element} elem The element to scroll.
      */
     getScrollPosition: function getPosition(elem) {
-        let style = util.computedStyle(elem);
+        let style = DOM(elem).style;
         return {
             x: elem.scrollLeft && elem.scrollLeft / this._exWidth(elem),
             y: elem.scrollTop / parseFloat(style.lineHeight)
@@ -1407,14 +1406,13 @@ var Buffer = Module("buffer", {
     },
 
     _exWidth: function _exWidth(elem) {
-        let div = elem.appendChild(
-            util.xmlToDom(<elem style="width: 1ex !important; position: absolute !important; padding: 0 !important; display: block;"/>,
-                          elem.ownerDocument));
+        let div = DOM(<elem style="width: 1ex !important; position: absolute !important; padding: 0 !important; display: block;"/>,
+                      elem.ownerDocument).appendTo(elem);
         try {
-            return parseFloat(util.computedStyle(div).width);
+            return parseFloat(div.style.width);
         }
         finally {
-            div.parentNode.removeChild(div);
+            div.remove();
         }
     },
 
@@ -1443,7 +1441,7 @@ var Buffer = Module("buffer", {
                 let arg = args[0];
 
                 // FIXME: arg handling is a bit of a mess, check for filename
-                dactyl.assert(!arg || arg[0] == ">" && !util.OS.isWindows,
+                dactyl.assert(!arg || arg[0] == ">" && !config.OS.isWindows,
                               _("error.trailingCharacters"));
 
                 const PRINTER = "PostScript/default";
@@ -1913,18 +1911,20 @@ var Buffer = Module("buffer", {
 
                     let frames = buffer.allFrames(null, true);
 
-                    let elements = array.flatten(frames.map(function (win) [m for (m in util.evaluateXPath(xpath, win.document))]))
+                    let elements = array.flatten(frames.map(function (win) [m for (m in DOM.XPath(xpath, win.document))]))
                                         .filter(function (elem) {
                         if (isinstance(elem, [HTMLFrameElement, HTMLIFrameElement]))
                             return Editor.getEditor(elem.contentWindow);
 
-                        if (elem.readOnly || elem instanceof HTMLInputElement && !Set.has(util.editableInputs, elem.type))
+                        elem = DOM(elem);
+
+                        if (elem[0].readOnly || !DOM(elem).isEditable)
                             return false;
 
-                        let computedStyle = util.computedStyle(elem);
-                        let rect = elem.getBoundingClientRect();
-                        return computedStyle.visibility != "hidden" && computedStyle.display != "none" &&
-                            (elem instanceof Ci.nsIDOMXULTextBoxElement || computedStyle.MozUserFocus != "ignore") &&
+                        let style = elem.style;
+                        let rect = elem.rect;
+                        return elem.isVisible &&
+                            (elem[0] instanceof Ci.nsIDOMXULTextBoxElement || style.MozUserFocus != "ignore") &&
                             rect.width && rect.height;
                     });
 
@@ -1932,7 +1932,7 @@ var Buffer = Module("buffer", {
                     elem = elements[Math.constrain(args.count, 1, elements.length) - 1];
                 }
                 buffer.focusElement(elem);
-                util.scrollIntoView(elem);
+                DOM(elem).scrollIntoView();
             },
             { count: true });
 
@@ -2086,10 +2086,10 @@ var Buffer = Module("buffer", {
                 keepQuotes: true,
                 setter: function (vals) {
                     for (let [k, v] in Iterator(vals))
-                        vals[k] = update(new String(v), { matcher: util.compileMatcher(Option.splitList(v)) });
+                        vals[k] = update(new String(v), { matcher: DOM.compileMatcher(Option.splitList(v)) });
                     return vals;
                 },
-                validator: function (value) util.validateMatcher.call(this, value)
+                validator: function (value) DOM.validateMatcher.call(this, value)
                     && Object.keys(value).every(function (v) v.length == 1)
             });
 
diff --git a/common/content/commandline.js b/common/content/commandline.js
index ca5b00d6..0675153b 100644
--- a/common/content/commandline.js
+++ b/common/content/commandline.js
@@ -279,7 +279,7 @@ var CommandWidgets = Class("CommandWidgets", {
             // some host apps use "hostPrefixContext-copy" ids
             let xpath = "//xul:menuitem[contains(@id, '" + "ontext-" + tail + "') and not(starts-with(@id, 'dactyl-'))]";
             document.getElementById("dactyl-context-" + tail).style.listStyleImage =
-                util.computedStyle(util.evaluateXPath(xpath, document).snapshotItem(0)).listStyleImage;
+                DOM(DOM.XPath(xpath, document).snapshotItem(0)).style.listStyleImage;
         });
         return document.getElementById("dactyl-contextmenu");
     }),
@@ -899,7 +899,7 @@ var CommandLine = Module("commandline", {
         this.savingOutput = true;
         dactyl.trapErrors.apply(dactyl, [fn, self].concat(Array.slice(arguments, 2)));
         this.savingOutput = false;
-        return output.map(function (elem) elem instanceof Node ? util.domToString(elem) : elem)
+        return output.map(function (elem) elem instanceof Node ? DOM.stringify(elem) : elem)
                      .join("\n");
     }
 }, {
@@ -1641,8 +1641,10 @@ var ItemList = Class("ItemList", {
     _init: function _init() {
         this._div = this._dom(
             <div class="ex-command-output" highlight="Normal" style="white-space: nowrap">
-                <div highlight="Completions" key="noCompletions"><span highlight="Title">{_("completion.noCompletions")}</span></div>
-                <div key="completions"/>
+                <div key="wrapper">
+                    <div highlight="Completions" key="noCompletions"><span highlight="Title">{_("completion.noCompletions")}</span></div>
+                    <div key="completions"/>
+                </div>
                 <div highlight="Completions">
                 {
                     template.map(util.range(0, options["maxitems"] * 2), function (i)
@@ -1653,7 +1655,7 @@ var ItemList = Class("ItemList", {
                 </div>
             </div>, this._divNodes);
         this._doc.body.replaceChild(this._div, this._doc.body.firstChild);
-        util.scrollIntoView(this._div, true);
+        DOM(this._divNodes.wrapper).scrollIntoView(true);
 
         this._items.contextList.forEach(function init_eachContext(context) {
             delete context.cache.nodes;
@@ -1758,7 +1760,7 @@ var ItemList = Class("ItemList", {
 
         this._divNodes.noCompletions.style.display = haveCompletions ? "none" : "block";
 
-        this._completionElements = util.evaluateXPath("//xhtml:div[@dactyl:highlight='CompItem']", this._doc);
+        this._completionElements = DOM.XPath("//xhtml:div[@dactyl:highlight='CompItem']", this._doc);
 
         return true;
     },
@@ -1828,7 +1830,7 @@ var ItemList = Class("ItemList", {
         if (index >= 0) {
             this._getCompletion(index).setAttribute("selected", "true");
             if (this._container.height != 0)
-                util.scrollIntoView(this._getCompletion(index));
+                DOM(this._getCompletion(index)).scrollIntoView();
         }
 
         //if (index == 0)
diff --git a/common/content/dactyl.js b/common/content/dactyl.js
index 8e0301d7..b9395f84 100644
--- a/common/content/dactyl.js
+++ b/common/content/dactyl.js
@@ -698,7 +698,7 @@ var Dactyl = Module("dactyl", XPCOM(Ci.nsISupportsWeakReference, ModuleBase), {
             };
             // Find the tags in the document.
             let addTags = function addTags(file, doc) {
-                for (let elem in util.evaluateXPath("//@tag|//dactyl:tags/text()|//dactyl:tag/text()", doc))
+                for (let elem in DOM.XPath("//@tag|//dactyl:tags/text()|//dactyl:tag/text()", doc))
                     for (let tag in values((elem.value || elem.textContent).split(/\s+/)))
                         tagMap[tag] = file;
             };
@@ -716,7 +716,7 @@ var Dactyl = Module("dactyl", XPCOM(Ci.nsISupportsWeakReference, ModuleBase), {
             tagMap["all"] = tagMap["all.xml"] = "all";
             tagMap["versions"] = tagMap["versions.xml"] = "versions";
             let files = findHelpFile("all").map(function (doc)
-                    [f.value for (f in util.evaluateXPath("//dactyl:include/@href", doc))]);
+                    [f.value for (f in DOM.XPath("//dactyl:include/@href", doc))]);
 
             // Scrape the tags from the rest of the help files.
             array.flatten(files).forEach(function (file) {
@@ -1255,10 +1255,11 @@ var Dactyl = Module("dactyl", XPCOM(Ci.nsISupportsWeakReference, ModuleBase), {
      * Opens one or more URLs. Returns true when load was initiated, or
      * false on error.
      *
-     * @param {string|Array} urls A representation of the URLs to open. May be
+     * @param {string|object|Array} urls A representation of the URLs to open. May be
      *     either a string, which will be passed to
-     *     {@see Dactyl#parseURLs}, or an array in the same format as
-     *     would be returned by the same.
+     *     {@link Dactyl#parseURLs}, an array in the same format as
+     *     would be returned by the same, or an object as returned by
+     *     {@link DOM#formData}.
      * @param {object} params A set of parameters specifying how to open the
      *     URLs. The following properties are recognized:
      *
@@ -1312,21 +1313,23 @@ var Dactyl = Module("dactyl", XPCOM(Ci.nsISupportsWeakReference, ModuleBase), {
             return;
 
         let browser = config.tabbrowser;
-        function open(urls, where) {
+        function open(loc, where) {
             try {
-                let url = Array.concat(urls)[0];
-                let postdata = Array.concat(urls)[1];
+                if (isArray(loc))
+                    loc = { url: loc[0], postData: loc[1] };
+                else if (isString(loc))
+                    loc = { url: loc };
 
                 // decide where to load the first url
                 switch (where) {
 
                 case dactyl.NEW_TAB:
                     if (!dactyl.has("tabs"))
-                        return open(urls, dactyl.NEW_WINDOW);
+                        return open(loc, dactyl.NEW_WINDOW);
 
                     return prefs.withContext(function () {
                         prefs.set("browser.tabs.loadInBackground", true);
-                        return browser.loadOneTab(url, null, null, postdata, background).linkedBrowser.contentDocument;
+                        return browser.loadOneTab(loc.url, null, null, loc.postData, background).linkedBrowser.contentDocument;
                     });
 
                 case dactyl.NEW_WINDOW:
@@ -1335,7 +1338,7 @@ var Dactyl = Module("dactyl", XPCOM(Ci.nsISupportsWeakReference, ModuleBase), {
                     browser = win.dactyl && win.dactyl.modules.config.tabbrowser || win.getBrowser();
                     // FALLTHROUGH
                 case dactyl.CURRENT_TAB:
-                    browser.loadURIWithFlags(url, flags, null, null, postdata);
+                    browser.loadURIWithFlags(loc.url, flags, null, null, loc.postData);
                     return browser.contentWindow;
                 }
             }
@@ -1380,7 +1383,7 @@ var Dactyl = Module("dactyl", XPCOM(Ci.nsISupportsWeakReference, ModuleBase), {
         return urls.map(function (url) {
             url = url.trim();
 
-            if (/^(\.{0,2}|~)(\/|$)/.test(url) || util.OS.isWindows && /^[a-z]:/i.test(url)) {
+            if (/^(\.{0,2}|~)(\/|$)/.test(url) || config.OS.isWindows && /^[a-z]:/i.test(url)) {
                 try {
                     // Try to find a matching file.
                     let file = io.File(url);
@@ -1945,7 +1948,7 @@ var Dactyl = Module("dactyl", XPCOM(Ci.nsISupportsWeakReference, ModuleBase), {
             function () { dactyl.restart(); },
             { argCount: "0" });
 
-        function findToolbar(name) util.evaluateXPath(
+        function findToolbar(name) DOM.XPath(
             "//*[@toolbarname=" + util.escapeString(name, "'") + " or " +
                 "@toolbarname=" + util.escapeString(name.trim(), "'") + "]",
             document).snapshotItem(0);
@@ -2136,7 +2139,7 @@ var Dactyl = Module("dactyl", XPCOM(Ci.nsISupportsWeakReference, ModuleBase), {
         completion.toolbar = function toolbar(context) {
             context.title = ["Toolbar"];
             context.keys = { text: function (item) item.getAttribute("toolbarname"), description: function () "" };
-            context.completions = util.evaluateXPath("//*[@toolbarname]", document);
+            context.completions = DOM.XPath("//*[@toolbarname]", document);
         };
 
         completion.window = function window(context) {
diff --git a/common/content/editor.js b/common/content/editor.js
index 1c50dac9..cc60c721 100644
--- a/common/content/editor.js
+++ b/common/content/editor.js
@@ -209,7 +209,7 @@ var Editor = Module("editor", {
             var editor_ = window.GetCurrentEditor ? GetCurrentEditor()
                                                   : Editor.getEditor(document.commandDispatcher.focusedWindow);
             dactyl.assert(editor_);
-            text = Array.map(editor_.rootElement.childNodes, function (e) util.domToString(e, true)).join("");
+            text = Array.map(editor_.rootElement.childNodes, function (e) DOM.stringify(e, true)).join("");
         }
 
         let origGroup = textBox && textBox.getAttributeNS(NS, "highlight") || "";
@@ -348,16 +348,7 @@ var Editor = Module("editor", {
             elem = dactyl.focusedElement || document.commandDispatcher.focusedWindow;
         dactyl.assert(elem);
 
-        try {
-            if (elem instanceof Element)
-                return elem.QueryInterface(Ci.nsIDOMNSEditableElement).editor;
-            return elem.QueryInterface(Ci.nsIInterfaceRequestor).getInterface(Ci.nsIWebNavigation)
-                       .QueryInterface(Ci.nsIInterfaceRequestor).getInterface(Ci.nsIEditingSession)
-                       .getEditorForWindow(elem);
-        }
-        catch (e) {
-            return null;
-        }
+        return DOM(elem).editor;
     },
 
     getController: function (cmd) {
@@ -582,7 +573,7 @@ var Editor = Module("editor", {
 
         addMotionMap("d", "Delete motion", true,  function (editor) { editor.cut(); });
         addMotionMap("c", "Change motion", true,  function (editor) { editor.cut(); }, modes.INSERT);
-        addMotionMap("y", "Yank motion",   false, function (editor, range) { dactyl.clipboardWrite(util.domToString(range)) });
+        addMotionMap("y", "Yank motion",   false, function (editor, range) { dactyl.clipboardWrite(DOM.stringify(range)) });
 
         let bind = function bind(names, description, action, params)
             mappings.add([modes.INPUT], names, description,
diff --git a/common/content/events.js b/common/content/events.js
index 1b3a3d80..6f3090df 100644
--- a/common/content/events.js
+++ b/common/content/events.js
@@ -495,12 +495,6 @@ var Events = Module("events", {
 
         this._activeMenubar = false;
         this.listen(window, this, "events");
-
-        util.windows = [window].concat(util.windows);
-    },
-
-    destroy: function destroy() {
-        util.windows = util.windows.filter(function (w) w != window);
     },
 
     signals: {
@@ -922,14 +916,14 @@ var Events = Module("events", {
             //         https://bugzilla.mozilla.org/show_bug.cgi?id=432951
             // ---
             //
-            // The following fixes are only activated if util.OS.isMacOSX.
+            // The following fixes are only activated if config.OS.isMacOSX.
             // Technically, they prevent mappings from <C-Esc> (and
             // <C-C-]> if your fancy keyboard permits such things<?>), but
             // these <C-control> mappings are probably pathological (<C-Esc>
             // certainly is on Windows), and so it is probably
-            // harmless to remove the util.OS.isMacOSX if desired.
+            // harmless to remove the config.OS.isMacOSX if desired.
             //
-            else if (util.OS.isMacOSX && event.ctrlKey && charCode >= 27 && charCode <= 31) {
+            else if (config.OS.isMacOSX && event.ctrlKey && charCode >= 27 && charCode <= 31) {
                 if (charCode == 27) { // [Ctrl-Bug 1/5] the <C-[> bug
                     key = "Esc";
                     modifier = modifier.replace("C-", "");
@@ -1019,7 +1013,7 @@ var Events = Module("events", {
                          ["key", key.toLowerCase()]);
         }
 
-        let accel = util.OS.isMacOSX ? "metaKey" : "ctrlKey";
+        let accel = config.OS.isMacOSX ? "metaKey" : "ctrlKey";
 
         let access = iter({ 1: "shiftKey", 2: "ctrlKey", 4: "altKey", 8: "metaKey" })
                         .filter(function ([k, v]) this & k, prefs.get("ui.key.chromeAccess"))
@@ -1160,7 +1154,7 @@ var Events = Module("events", {
             let elem = event.originalTarget;
 
             if (elem == window)
-                util.windows = [window].concat(util.windows.filter(function (w) w != window));
+                overlay.activeWindow = window;
 
             elem.dactylHadFocus = true;
             if (event.target instanceof Ci.nsIDOMXULTextBoxElement)
@@ -1444,7 +1438,7 @@ var Events = Module("events", {
             let haveInput = modes.stack.some(function (m) m.main.input);
 
             if (elem instanceof HTMLTextAreaElement
-               || elem instanceof Element && util.computedStyle(elem).MozUserModify === "read-write"
+               || elem instanceof Element && DOM(elem).style.MozUserModify === "read-write"
                || elem == null && win && Editor.getEditor(win)) {
 
                 if (modes.main == modes.VISUAL && elem.selectionEnd == elem.selectionStart)
@@ -1525,7 +1519,7 @@ var Events = Module("events", {
             key === "<Esc>" || key === "<C-[>",
 
     isHidden: function isHidden(elem, aggressive) {
-        if (util.computedStyle(elem).visibility !== "visible")
+        if (DOM(elem).style.visibility !== "visible")
             return true;
 
         if (aggressive)
@@ -1539,12 +1533,9 @@ var Events = Module("events", {
     },
 
     isInputElement: function isInputElement(elem) {
-        return elem instanceof HTMLInputElement && Set.has(util.editableInputs, elem.type) ||
-               isinstance(elem, [HTMLEmbedElement,
-                                 HTMLObjectElement, HTMLSelectElement,
-                                 HTMLTextAreaElement,
-                                 Ci.nsIDOMXULTextBoxElement]) ||
-               elem instanceof Window && Editor.getEditor(elem);
+        return DOM(elem).isEditable ||
+               isinstance(elem, [HTMLEmbedElement, HTMLObjectElement,
+                                 HTMLSelectElement])
     },
 
     kill: function kill(event) {
diff --git a/common/content/hints.js b/common/content/hints.js
index 459ac88a..2c4b29ed 100644
--- a/common/content/hints.js
+++ b/common/content/hints.js
@@ -255,7 +255,7 @@ var HintSession = Class("HintSession", CommandMode, {
     getContainerOffsets: function _getContainerOffsets(doc) {
         let body = doc.body || doc.documentElement;
         // TODO: getComputedStyle returns null for Facebook channel_iframe doc - probable Gecko bug.
-        let style = util.computedStyle(body);
+        let style = DOM(body).style;
 
         if (style && /^(absolute|fixed|relative)$/.test(style.position)) {
             let rect = body.getClientRects()[0];
@@ -298,7 +298,7 @@ var HintSession = Class("HintSession", CommandMode, {
                 return false;
 
             if (!rect.width || !rect.height)
-                if (!Array.some(elem.childNodes, function (elem) elem instanceof Element && util.computedStyle(elem).float != "none" && isVisible(elem)))
+                if (!Array.some(elem.childNodes, function (elem) elem instanceof Element && DOM(elem).style.float != "none" && isVisible(elem)))
                     return false;
 
             let computedStyle = doc.defaultView.getComputedStyle(elem, null);
@@ -309,12 +309,11 @@ var HintSession = Class("HintSession", CommandMode, {
 
         let body = doc.body || doc.querySelector("body");
         if (body) {
-            let fragment = util.xmlToDom(<div highlight="hints"/>, doc);
-            body.appendChild(fragment);
-            util.computedStyle(fragment).height; // Force application of binding.
-            let container = doc.getAnonymousElementByAttribute(fragment, "anonid", "hints") || fragment;
+            let fragment = DOM(<div highlight="hints"/>, doc).appendTo(body);
+            fragment.style.height; // Force application of binding.
+            let container = doc.getAnonymousElementByAttribute(fragment[0], "anonid", "hints") || fragment[0];
 
-            let baseNodeAbsolute = util.xmlToDom(<span highlight="Hint" style="display: none;"/>, doc);
+            let baseNode = DOM(<span highlight="Hint" style="display: none;"/>, doc)[0];
 
             let mode = this.hintMode;
             let res = mode.matcher(doc);
@@ -342,7 +341,7 @@ var HintSession = Class("HintSession", CommandMode, {
                 else
                     hint.text = elem.textContent.toLowerCase();
 
-                hint.span = baseNodeAbsolute.cloneNode(false);
+                hint.span = baseNode.cloneNode(false);
 
                 let leftPos = Math.max((rect.left + offsetX), offsetX);
                 let topPos  = Math.max((rect.top + offsetY), offsetY);
@@ -532,7 +531,7 @@ var HintSession = Class("HintSession", CommandMode, {
             // Goddamn stupid fucking Gecko 1.x security manager bullshit.
             try { delete doc.dactylLabels; } catch (e) { doc.dactylLabels = undefined; }
 
-            for (let elem in util.evaluateXPath("//*[@dactyl:highlight='hints']", doc))
+            for (let elem in DOM.XPath("//*[@dactyl:highlight='hints']", doc))
                 elem.parentNode.removeChild(elem);
             for (let i in util.range(start, end + 1)) {
                 this.pageHints[i].ambiguous = false;
@@ -824,7 +823,7 @@ var Hints = Module("hints", {
 
         let type = elem.type;
 
-        if (elem instanceof HTMLInputElement && Set.has(util.editableInputs, elem.type))
+        if (DOM(elem).isInput)
             return [elem.value, false];
         else {
             for (let [, option] in Iterator(options["hintinputs"])) {
@@ -1080,7 +1079,7 @@ var Hints = Module("hints", {
     isVisible: function isVisible(elem, offScreen) {
         let rect = elem.getBoundingClientRect();
         if (!rect.width || !rect.height)
-            if (!Array.some(elem.childNodes, function (elem) elem instanceof Element && util.computedStyle(elem).float != "none" && isVisible(elem)))
+            if (!Array.some(elem.childNodes, function (elem) elem instanceof Element && DOM(elem).style.float != "none" && isVisible(elem)))
                 return false;
 
         let win = elem.ownerDocument.defaultView;
@@ -1089,8 +1088,7 @@ var Hints = Module("hints", {
                           rect.right + win.scrollX > win.scrolMaxX + win.innerWidth))
             return false;
 
-        let computedStyle = util.computedStyle(elem, null);
-        if (computedStyle.visibility != "visible" || computedStyle.display == "none")
+        if (!DOM(elem).isVisible)
             return false;
         return true;
     },
@@ -1249,8 +1247,6 @@ var Hints = Module("hints", {
             function ({ self }) { self.escapeNumbers = !self.escapeNumbers; });
     },
     options: function () {
-        function xpath(arg) util.makeXPath(arg);
-
         options.add(["extendedhinttags", "eht"],
             "XPath or CSS selector strings of hintable elements for extended hint modes",
             "regexpmap", {
@@ -1267,10 +1263,10 @@ var Hints = Module("hints", {
                         res ? res.matcher : default_,
                 setter: function (vals) {
                     for (let value in values(vals))
-                        value.matcher = util.compileMatcher(Option.splitList(value.result));
+                        value.matcher = DOM.compileMatcher(Option.splitList(value.result));
                     return vals;
                 },
-                validator: util.validateMatcher
+                validator: DOM.validateMatcher
             });
 
         options.add(["hinttags", "ht"],
@@ -1280,10 +1276,10 @@ var Hints = Module("hints", {
                           "[tabindex],[role=link],[role=button],[contenteditable=true]",
             {
                 setter: function (values) {
-                    this.matcher = util.compileMatcher(values);
+                    this.matcher = DOM.compileMatcher(values);
                     return values;
                 },
-                validator: util.validateMatcher
+                validator: DOM.validateMatcher
             });
 
         options.add(["hintkeys", "hk"],
diff --git a/common/content/marks.js b/common/content/marks.js
index e6bbb9b4..13355261 100644
--- a/common/content/marks.js
+++ b/common/content/marks.js
@@ -42,7 +42,7 @@ var Marks = Module("marks", {
 
         params.location = doc.documentURI,
         params.offset = buffer.scrollPosition;
-        params.path = util.generateXPath(buffer.findScrollable(0, params.offset.x));
+        params.path = DOM(buffer.findScrollable(0, params.offset.x)).xpath;
         params.timestamp = Date.now() * 1000;
         params.equals = function (m) this.location == m.location
                                   && this.offset.x == m.offset.x
@@ -227,11 +227,11 @@ var Marks = Module("marks", {
         if (!mark.xpath)
             var node = buffer.findScrollable(0, (mark.offset || mark.position).x)
         else
-            for (node in util.evaluateXPath(mark.xpath, buffer.focusedFrame.document))
+            for (node in DOM.XPath(mark.xpath, buffer.focusedFrame.document))
                 break;
 
         util.assert(node);
-        util.scrollIntoView(node);
+        DOM(node).scrollIntoView();
 
         if (mark.offset)
             Buffer.scrollToPosition(node, mark.offset.x, mark.offset.y);
diff --git a/common/content/mow.js b/common/content/mow.js
index bd055746..4254cb9c 100644
--- a/common/content/mow.js
+++ b/common/content/mow.js
@@ -24,7 +24,7 @@ var MOW = Module("mow", {
                 if (options["more"] && this.isScrollable(1)) {
                     // start the last executed command's output at the top of the screen
                     let elements = this.document.getElementsByClassName("ex-command-output");
-                    elements[elements.length - 1].scrollIntoView(true);
+                    DOM(elements[elements.length - 1]).scrollIntoView(true);
                 }
                 else
                     this.body.scrollTop = this.body.scrollHeight;
@@ -37,7 +37,7 @@ var MOW = Module("mow", {
         events.listen(window, this, "windowEvents");
 
         modules.mow = this;
-        let fontSize = util.computedStyle(document.documentElement).fontSize;
+        let fontSize = DOM(document.documentElement).style.fontSize;
         styles.system.add("font-size", "dactyl://content/buffer.xhtml",
                           "body { font-size: " + fontSize + "; } \
                            html|html > xul|scrollbar { visibility: collapse !important; }",
@@ -94,7 +94,7 @@ var MOW = Module("mow", {
      * @param {string} highlightGroup
      */
     echo: function echo(data, highlightGroup, silent) {
-        let body = this.document.body;
+        let body = DOM(this.document.body);
 
         this.widgets.message = null;
         if (!commandline.commandVisible)
@@ -122,11 +122,11 @@ var MOW = Module("mow", {
         if (isObject(data) && !isinstance(data, _)) {
             this.lastOutput = null;
 
-            var output = util.xmlToDom(<div class="ex-command-output" style="white-space: nowrap" highlight={highlightGroup}/>,
-                                       this.document);
+            var output = DOM(<div class="ex-command-output" style="white-space: nowrap" highlight={highlightGroup}/>,
+                             this.document);
             data.document = this.document;
             try {
-                output.appendChild(data.message);
+                output.append(data.message);
             }
             catch (e) {
                 util.reportError(e);
@@ -138,17 +138,17 @@ var MOW = Module("mow", {
             let style = isString(data) ? "pre-wrap" : "nowrap";
             this.lastOutput = <div class="ex-command-output" style={"white-space: " + style} highlight={highlightGroup}>{data}</div>;
 
-            var output = util.xmlToDom(this.lastOutput, this.document);
+            var output = DOM(this.lastOutput, this.document);
         }
 
         // FIXME: need to make sure an open MOW is closed when commands
         //        that don't generate output are executed
         if (!this.visible) {
             this.body.scrollTop = 0;
-            body.textContent = "";
+            body.empty();
         }
 
-        body.appendChild(output);
+        body.append(output);
 
         let str = typeof data !== "xml" && data.message || data;
         if (!silent)
diff --git a/common/content/statusline.js b/common/content/statusline.js
index b5dbee70..2d93e512 100644
--- a/common/content/statusline.js
+++ b/common/content/statusline.js
@@ -42,7 +42,7 @@ var StatusLine = Module("statusline", {
                     color: inherit !important;
                 }
                 AddonButton:not(:hover)  background: transparent;
-            ]]>)({ padding: util.OS.isMacOSX ? "padding-right: 10px !important;" : "" }));
+            ]]>)({ padding: config.OS.isMacOSX ? "padding-right: 10px !important;" : "" }));
 
             if (document.getElementById("appmenu-button"))
                 highlight.loadCSS(<![CDATA[
diff --git a/common/content/tabs.js b/common/content/tabs.js
index 3d9e6c7f..c5c156c0 100644
--- a/common/content/tabs.js
+++ b/common/content/tabs.js
@@ -37,7 +37,7 @@ var Tabs = Module("tabs", {
 
         this.tabBinding = styles.system.add("tab-binding", "chrome://browser/content/browser.xul", String.replace(<><![CDATA[
                 xul|tab { -moz-binding: url(chrome://dactyl/content/bindings.xml#tab) !important; }
-            ]]></>, /tab-./g, function (m) util.OS.isMacOSX ? "tab-mac" : m),
+            ]]></>, /tab-./g, function (m) config.OS.isMacOSX ? "tab-mac" : m),
             false, true);
 
         this.timeout(function () {
@@ -75,14 +75,12 @@ var Tabs = Module("tabs", {
                 if (!node("dactyl-tab-number")) {
                     let img = node("tab-icon-image");
                     if (img) {
-                        let nodes = {};
-                        let dom = util.xmlToDom(<xul xmlns:xul={XUL} xmlns:html={XHTML}
+                        let dom = DOM(<xul xmlns:xul={XUL} xmlns:html={XHTML}
                             ><xul:hbox highlight="tab-number"><xul:label key="icon" align="center" highlight="TabIconNumber" class="dactyl-tab-icon-number"/></xul:hbox
                             ><xul:hbox highlight="tab-number"><html:div key="label" highlight="TabNumber" class="dactyl-tab-number"/></xul:hbox
-                        ></xul>.*, document, nodes);
-                        img.parentNode.appendChild(dom);
-                        tab.__defineGetter__("dactylOrdinal", function () Number(nodes.icon.value));
-                        tab.__defineSetter__("dactylOrdinal", function (i) nodes.icon.value = nodes.label.textContent = i);
+                        ></xul>.*, document).appendTo(img.parentNode);
+                        tab.__defineGetter__("dactylOrdinal", function () Number(dom.nodes.icon.value));
+                        tab.__defineSetter__("dactylOrdinal", function (i) dom.nodes.icon.value = dom.nodes.label.textContent = i);
                     }
                 }
             }
diff --git a/common/modules/addons.jsm b/common/modules/addons.jsm
index 6f43950c..160b3178 100644
--- a/common/modules/addons.jsm
+++ b/common/modules/addons.jsm
@@ -111,7 +111,7 @@ var actions = {
         name: "extr[ehash]",
         description: "Reload an extension",
         action: function (addon) {
-            util.assert(util.haveGecko("2b"), _("command.notUseful", config.host));
+            util.assert(config.haveGecko("2b"), _("command.notUseful", config.host));
             util.timeout(function () {
                 addon.userDisabled = true;
                 addon.userDisabled = false;
diff --git a/common/modules/base.jsm b/common/modules/base.jsm
index 0c8c82f4..8cde5ce2 100644
--- a/common/modules/base.jsm
+++ b/common/modules/base.jsm
@@ -144,6 +144,7 @@ function defineModule(name, params, module) {
             use[mod] = use[mod] || [];
             use[mod].push(module);
         }
+    module._lastModule = currentModule;
     currentModule = module;
     module.startTime = Date.now();
 }
@@ -190,6 +191,7 @@ function endModule() {
         require(mod, currentModule.NAME, "use");
 
     loaded[currentModule.NAME] = 1;
+    currentModule = currentModule._lastModule;
 }
 
 function require(obj, name, from) {
@@ -732,7 +734,7 @@ function Class() {
     if (callable(args[0]))
         superclass = args.shift();
 
-    if (loaded.util && util.haveGecko("6.0a1")) // Bug 657418.
+    if (loaded.config && config.haveGecko("6.0a1")) // Bug 657418.
         var Constructor = function Constructor() {
             var self = Object.create(Constructor.prototype, {
                 constructor: { value: Constructor },
diff --git a/common/modules/config.jsm b/common/modules/config.jsm
index 4da5a88d..2623b84b 100644
--- a/common/modules/config.jsm
+++ b/common/modules/config.jsm
@@ -23,7 +23,7 @@ var ConfigBase = Class("ConfigBase", {
      */
     init: function init() {
         this.features.push = deprecated("Set.add", function push(feature) Set.add(this, feature));
-        if (util.haveGecko("2b"))
+        if (this.haveGecko("2b"))
             Set.add(this.features, "Gecko2");
 
         this.timeout(function () {
@@ -40,7 +40,7 @@ var ConfigBase = Class("ConfigBase", {
         highlight.loadCSS(this.CSS.replace(/__MSG_(.*?)__/g, function (m0, m1) _(m1)));
         highlight.loadCSS(this.helpCSS.replace(/__MSG_(.*?)__/g, function (m0, m1) _(m1)));
 
-        if (!util.haveGecko("2b"))
+        if (!this.haveGecko("2b"))
             highlight.loadCSS(<![CDATA[
                 !TabNumber               font-weight: bold; margin: 0px; padding-right: .8ex;
                 !TabIconNumber {
@@ -60,12 +60,12 @@ var ConfigBase = Class("ConfigBase", {
 
             let elem = services.appShell.hiddenDOMWindow.document.createElement("div");
             elem.style.cssText = this.cssText;
-            let style = util.computedStyle(elem);
 
             let keys = iter(Styles.propertyIter(this.cssText)).map(function (p) p.name).toArray();
             let bg = keys.some(function (k) /^background/.test(k));
             let fg = keys.indexOf("color") >= 0;
 
+            let style = DOM(elem).style;
             prefs[bg ? "safeSet" : "safeReset"]("ui.textHighlightBackground", hex(style.backgroundColor));
             prefs[fg ? "safeSet" : "safeReset"]("ui.textHighlightForeground", hex(style.color));
         };
@@ -149,6 +149,87 @@ var ConfigBase = Class("ConfigBase", {
     },
 
     /**
+     * A list of all known registered chrome and resource packages.
+     */
+    get chromePackages() {
+        // Horrible hack.
+        let res = {};
+        function process(manifest) {
+            for each (let line in manifest.split(/\n+/)) {
+                let match = /^\s*(content|skin|locale|resource)\s+([^\s#]+)\s/.exec(line);
+                if (match)
+                    res[match[2]] = true;
+            }
+        }
+        function processJar(file) {
+            let jar = services.ZipReader(file);
+            if (jar) {
+                if (jar.hasEntry("chrome.manifest"))
+                    process(File.readStream(jar.getInputStream("chrome.manifest")));
+                jar.close();
+            }
+        }
+
+        for each (let dir in ["UChrm", "AChrom"]) {
+            dir = File(services.directory.get(dir, Ci.nsIFile));
+            if (dir.exists() && dir.isDirectory())
+                for (let file in dir.iterDirectory())
+                    if (/\.manifest$/.test(file.leafName))
+                        process(file.read());
+
+            dir = File(dir.parent);
+            if (dir.exists() && dir.isDirectory())
+                for (let file in dir.iterDirectory())
+                    if (/\.jar$/.test(file.leafName))
+                        processJar(file);
+
+            dir = dir.child("extensions");
+            if (dir.exists() && dir.isDirectory())
+                for (let ext in dir.iterDirectory()) {
+                    if (/\.xpi$/.test(ext.leafName))
+                        processJar(ext);
+                    else {
+                        if (ext.isFile())
+                            ext = File(ext.read().replace(/\n*$/, ""));
+                        let mf = ext.child("chrome.manifest");
+                        if (mf.exists())
+                            process(mf.read());
+                    }
+                }
+        }
+        return Object.keys(res).sort();
+    },
+
+    /**
+     * Returns true if the current Gecko runtime is of the given version
+     * or greater.
+     *
+     * @param {string} ver The required version.
+     * @returns {boolean}
+     */
+    haveGecko: function (ver) services.versionCompare.compare(services.runtime.platformVersion, ver) >= 0,
+
+    /** Dactyl's notion of the current operating system platform. */
+    OS: memoize({
+        _arch: services.runtime.OS,
+        /**
+         * @property {string} The normalised name of the OS. This is one of
+         *     "Windows", "Mac OS X" or "Unix".
+         */
+        get name() this.isWindows ? "Windows" : this.isMacOSX ? "Mac OS X" : "Unix",
+        /** @property {boolean} True if the OS is Windows. */
+        get isWindows() this._arch == "WINNT",
+        /** @property {boolean} True if the OS is Mac OS X. */
+        get isMacOSX() this._arch == "Darwin",
+        /** @property {boolean} True if the OS is some other *nix variant. */
+        get isUnix() !this.isWindows && !this.isMacOSX,
+        /** @property {RegExp} A RegExp which matches illegal characters in path components. */
+        get illegalCharacters() this.isWindows ? /[<>:"/\\|?*\x00-\x1f]/g : /\//g,
+
+        get pathListSep() this.isWindows ? ";" : ":"
+    }),
+
+    /**
      * @property {string} The pathname of the VCS repository clone's root
      *     directory if the application is running from one via an extension
      *     proxy file.
diff --git a/common/modules/finder.jsm b/common/modules/finder.jsm
index 6ff2caee..94f9e48a 100644
--- a/common/modules/finder.jsm
+++ b/common/modules/finder.jsm
@@ -403,8 +403,8 @@ var RangeFind = Class("RangeFind", {
 
     focus: function focus() {
         if (this.lastRange)
-            var node = util.evaluateXPath(RangeFind.selectNodePath,
-                                          this.lastRange.commonAncestorContainer).snapshotItem(0);
+            var node = DOM.XPath(RangeFind.selectNodePath,
+                                 this.lastRange.commonAncestorContainer).snapshotItem(0);
         if (node) {
             node.focus();
             // Re-highlight collapsed selection
@@ -517,7 +517,7 @@ var RangeFind = Class("RangeFind", {
 
             for (let frame in array.iterValues(win.frames)) {
                 let range = doc.createRange();
-                if (util.computedStyle(frame.frameElement).visibility == "visible") {
+                if (DOM(frame.frameElement).style.visibility == "visible") {
                     range.selectNode(frame.frameElement);
                     pushRange(pageStart, RangeFind.endpoint(range, true));
                     pageStart = RangeFind.endpoint(range, false);
diff --git a/common/modules/io.jsm b/common/modules/io.jsm
index 59eb8d98..aeead9b3 100644
--- a/common/modules/io.jsm
+++ b/common/modules/io.jsm
@@ -299,7 +299,7 @@ var IO = Module("io", {
         let rcFile1 = dir.child("." + config.name + "rc");
         let rcFile2 = dir.child("_" + config.name + "rc");
 
-        if (util.OS.isWindows)
+        if (config.OS.isWindows)
             [rcFile1, rcFile2] = [rcFile2, rcFile1];
 
         if (rcFile1.exists() && rcFile1.isFile())
@@ -393,9 +393,9 @@ var IO = Module("io", {
         if (bin instanceof File || File.isAbsolutePath(bin))
             return this.File(bin);
 
-        let dirs = services.environment.get("PATH").split(util.OS.isWindows ? ";" : ":");
+        let dirs = services.environment.get("PATH").split(config.OS.isWindows ? ";" : ":");
         // Windows tries the CWD first TODO: desirable?
-        if (util.OS.isWindows)
+        if (config.OS.isWindows)
             dirs = [io.cwd].concat(dirs);
 
         for (let [, dir] in Iterator(dirs))
@@ -408,7 +408,7 @@ var IO = Module("io", {
 
                 // TODO: couldn't we just palm this off to the start command?
                 // automatically try to add the executable path extensions on windows
-                if (util.OS.isWindows) {
+                if (config.OS.isWindows) {
                     let extensions = services.environment.get("PATHEXT").split(";");
                     for (let [, extension] in Iterator(extensions)) {
                         file = dir.child(bin + extension);
@@ -478,7 +478,7 @@ var IO = Module("io", {
     system: function (command, input, callback) {
         util.dactyl.echomsg(_("io.callingShell", command), 4);
 
-        function escape(str) '"' + String.replace(str, /[\\"$]/g, "\\$&") + '"';
+        let { shellEscape } = util.closure;
 
         return this.withTempFiles(function (stdin, stdout, cmd) {
             if (input instanceof File)
@@ -505,17 +505,17 @@ var IO = Module("io", {
             util.assert(shell, _("error.invalid", "'shell'"));
 
             if (isArray(command))
-                command = command.map(escape).join(" ");
+                command = command.map(shellEscape).join(" ");
 
             // TODO: implement 'shellredir'
-            if (util.OS.isWindows && !/sh/.test(shell.leafName)) {
+            if (config.OS.isWindows && !/sh/.test(shell.leafName)) {
                 command = "cd /D " + this.cwd.path + " && " + command + " > " + stdout.path + " 2>&1" + " < " + stdin.path;
                 var res = this.run(shell, shcf.split(/\s+/).concat(command), callback ? async : true);
             }
             else {
-                cmd.write("cd " + escape(this.cwd.path) + "\n" +
-                        ["exec", ">" + escape(stdout.path), "2>&1", "<" + escape(stdin.path),
-                         escape(shell.path), shcf, escape(command)].join(" "));
+                cmd.write("cd " + shellEscape(this.cwd.path) + "\n" +
+                        ["exec", ">" + shellEscape(stdout.path), "2>&1", "<" + shellEscape(stdin.path),
+                         shellEscape(shell.path), shcf, shellEscape(command)].join(" "));
                 res = this.run("/bin/sh", ["-e", cmd.path], callback ? async : true);
             }
 
@@ -556,7 +556,7 @@ var IO = Module("io", {
         const rtpvar = config.idName + "_RUNTIME";
         let rtp = services.environment.get(rtpvar);
         if (!rtp) {
-            rtp = "~/" + (util.OS.isWindows ? "" : ".") + config.name;
+            rtp = "~/" + (config.OS.isWindows ? "" : ".") + config.name;
             services.environment.set(rtpvar, rtp);
         }
         return rtp;
@@ -644,7 +644,7 @@ var IO = Module("io", {
         commands.add(["mks[yntax]"],
             "Generate a Vim syntax file",
             function (args) {
-                let runtime = util.OS.isWindows ? "~/vimfiles/" : "~/.vim/";
+                let runtime = config.OS.isWindows ? "~/vimfiles/" : "~/.vim/";
                 let file = io.File(runtime + "syntax/" + config.name + ".vim");
                 if (args.length)
                     file = io.File(args[0]);
@@ -886,7 +886,7 @@ unlet s:cpo_save
         completion.environment = function environment(context) {
             context.title = ["Environment Variable", "Value"];
             context.generate = function ()
-                io.system(util.OS.isWindows ? "set" : "env")
+                io.system(config.OS.isWindows ? "set" : "env")
                   .output.split("\n")
                   .filter(function (line) line.indexOf("=") > 0)
                   .map(function (line) line.match(/([^=]+)=(.*)/).slice(1));
@@ -956,7 +956,7 @@ unlet s:cpo_save
         completion.shellCommand = function shellCommand(context) {
             context.title = ["Shell Command", "Path"];
             context.generate = function () {
-                let dirNames = services.environment.get("PATH").split(util.OS.isWindows ? ";" : ":");
+                let dirNames = services.environment.get("PATH").split(config.OS.pathListSep);
                 let commands = [];
 
                 for (let [, dirName] in Iterator(dirNames)) {
@@ -987,7 +987,7 @@ unlet s:cpo_save
                 if (!match.path) {
                     context.key = match.proto;
                     context.advance(match.proto.length);
-                    context.generate = function () util.chromePackages.map(function (p) [p, match.proto + p + "/"]);
+                    context.generate = function () config.chromePackages.map(function (p) [p, match.proto + p + "/"]);
                 }
                 else if (match.scheme === "chrome") {
                     context.key = match.prefix;
@@ -1001,7 +1001,7 @@ unlet s:cpo_save
             }
             if (!match || match.scheme === "resource" && match.path)
                 if (/^(\.{0,2}|~)\/|^file:/.test(context.filter)
-                    || util.OS.isWindows && /^[a-z]:/i.test(context.filter)
+                    || config.OS.isWindows && /^[a-z]:/i.test(context.filter)
                     || util.getFile(context.filter)
                     || io.isJarURL(context.filter))
                     completion.file(context, full);
@@ -1030,7 +1030,7 @@ unlet s:cpo_save
         const { completion, options } = modules;
 
         var shell, shellcmdflag;
-        if (util.OS.isWindows) {
+        if (config.OS.isWindows) {
             shell = "cmd.exe";
             shellcmdflag = "/c";
         }
@@ -1077,7 +1077,7 @@ unlet s:cpo_save
             "string", shellcmdflag,
             {
                 getter: function (value) {
-                    if (this.hasChanged || !util.OS.isWindows)
+                    if (this.hasChanged || !config.OS.isWindows)
                         return value;
                     return /sh/.test(options["shell"]) ? "-c" : "/c";
                 }
diff --git a/common/modules/overlay.jsm b/common/modules/overlay.jsm
index 08c2829d..ec329f05 100644
--- a/common/modules/overlay.jsm
+++ b/common/modules/overlay.jsm
@@ -8,7 +8,7 @@ try {
 
 Components.utils.import("resource://dactyl/bootstrap.jsm");
 defineModule("overlay", {
-    exports: ["ModuleBase"],
+    exports: ["ModuleBase", "overlay"],
     require: ["config", "io", "services", "util"]
 }, this);
 
@@ -28,11 +28,13 @@ var ModuleBase = Class("ModuleBase", {
 
 var Overlay = Module("Overlay", {
     init: function init() {
+        let overlay = this;
+
         services["dactyl:"]; // Hack. Force module initialization.
 
         config.loadStyles();
 
-        util.overlayWindow(config.overlayChrome, function overlay(window) ({
+        util.overlayWindow(config.overlayChrome, function _overlay(window) ({
             init: function onInit(document) {
                 /**
                  * @constructor Module
@@ -308,9 +310,15 @@ var Overlay = Module("Overlay", {
 
                 defineModule.loadLog.push("Loaded in " + (Date.now() - start) + "ms");
 
+                util.dump(overlay);
+
+                overlay.windows = array.uniq(overlay.windows.concat(window), true);
+
                 modules.events.listen(window, "unload", function onUnload() {
                     window.removeEventListener("unload", onUnload.wrapped, false);
 
+                    overlay.windows = overlay.windows.filter(function (w) w != window);
+
                     for each (let mod in modules.moduleList.reverse()) {
                         mod.stale = true;
 
@@ -320,7 +328,19 @@ var Overlay = Module("Overlay", {
                 }, false);
             }
         }));
-    }
+    },
+
+    /**
+     * The most recently active dactyl window.
+     */
+    get activeWindow() this.windows[0],
+
+    set activeWindow(win) this.windows = [win].concat(this.windows.filter(function (w) w != win)),
+
+    /**
+     * A list of extant dactyl windows.
+     */
+    windows: Class.memoize(function () [])
 });
 
 endModule();
diff --git a/common/modules/styles.jsm b/common/modules/styles.jsm
index 65c32ec2..d164c92e 100644
--- a/common/modules/styles.jsm
+++ b/common/modules/styles.jsm
@@ -702,7 +702,7 @@ var Styles = Module("Styles", {
             }));
     },
     completion: function (dactyl, modules, window) {
-        const names = Array.slice(util.computedStyle(window.document.createElement("div")));
+        const names = Array.slice(DOM(<div/>, window.document).style);
         modules.completion.css = function (context) {
             context.title = ["CSS Property"];
             context.keys = { text: function (p) p + ":", description: function () "" };
diff --git a/common/modules/util.jsm b/common/modules/util.jsm
index 59ba36bd..eeae6adf 100644
--- a/common/modules/util.jsm
+++ b/common/modules/util.jsm
@@ -13,7 +13,7 @@ Components.utils.import("resource://dactyl/bootstrap.jsm");
 defineModule("util", {
     exports: ["$", "DOM", "FailedAssertion", "Math", "NS", "Point", "Util", "XBL", "XHTML", "XUL", "util"],
     require: ["services"],
-    use: ["commands", "config", "highlight", "messages", "storage", "template"]
+    use: ["commands", "config", "highlight", "messages", "overlay", "storage", "template"]
 }, this);
 
 var XBL = Namespace("xbl", "http://www.mozilla.org/xbl");
@@ -85,7 +85,7 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
         }
     },
 
-    get activeWindow() this.windows[0],
+    activeWindow: deprecated("overlay.activeWindow", { get: function activeWindow() overlay.activeWindow }),
 
     dactyl: update(function dactyl(obj) {
         if (obj)
@@ -93,7 +93,7 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
 
         return {
             __noSuchMethod__: function (meth, args) {
-                let win = util.activeWindow;
+                let win = overlay.activeWindow;
 
                 var dactyl = global && global.dactyl || win && win.dactyl;
                 if (!dactyl)
@@ -204,55 +204,6 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
         return RegExp("[" + util.regexp.escape(list) + "]");
     },
 
-    get chromePackages() {
-        // Horrible hack.
-        let res = {};
-        function process(manifest) {
-            for each (let line in manifest.split(/\n+/)) {
-                let match = /^\s*(content|skin|locale|resource)\s+([^\s#]+)\s/.exec(line);
-                if (match)
-                    res[match[2]] = true;
-            }
-        }
-        function processJar(file) {
-            let jar = services.ZipReader(file);
-            if (jar) {
-                if (jar.hasEntry("chrome.manifest"))
-                    process(File.readStream(jar.getInputStream("chrome.manifest")));
-                jar.close();
-            }
-        }
-
-        for each (let dir in ["UChrm", "AChrom"]) {
-            dir = File(services.directory.get(dir, Ci.nsIFile));
-            if (dir.exists() && dir.isDirectory())
-                for (let file in dir.iterDirectory())
-                    if (/\.manifest$/.test(file.leafName))
-                        process(file.read());
-
-            dir = File(dir.parent);
-            if (dir.exists() && dir.isDirectory())
-                for (let file in dir.iterDirectory())
-                    if (/\.jar$/.test(file.leafName))
-                        processJar(file);
-
-            dir = dir.child("extensions");
-            if (dir.exists() && dir.isDirectory())
-                for (let ext in dir.iterDirectory()) {
-                    if (/\.xpi$/.test(ext.leafName))
-                        processJar(ext);
-                    else {
-                        if (ext.isFile())
-                            ext = File(ext.read().replace(/\n*$/, ""));
-                        let mf = ext.child("chrome.manifest");
-                        if (mf.exists())
-                            process(mf.read());
-                    }
-                }
-        }
-        return Object.keys(res).sort();
-    },
-
     /**
      * Returns a shallow copy of *obj*.
      *
@@ -451,79 +402,24 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
         return stack.top;
     },
 
-    /**
-     * Compiles a CSS spec and XPath pattern matcher based on the given
-     * list. List elements prefixed with "xpath:" are parsed as XPath
-     * patterns, while other elements are parsed as CSS specs. The
-     * returned function will, given a node, return an iterator of all
-     * descendants of that node which match the given specs.
-     *
-     * @param {[string]} list The list of patterns to match.
-     * @returns {function(Node)}
-     */
-    compileMatcher: function compileMatcher(list) {
-        let xpath = [], css = [];
-        for (let elem in values(list))
-            if (/^xpath:/.test(elem))
-                xpath.push(elem.substr(6));
-            else
-                css.push(elem);
+    compileMatcher: deprecated("DOM.compileMatcher", { get: function compileMatcher() DOM.compileMatcher }),
+    computedStyle: deprecated("DOM#style", function computedStyle(elem) DOM(elem).style),
+    domToString: deprecated("DOM.stringify", { get: function domToString() DOM.stringify }),
+    editableInputs: deprecated("DOM.editableInputs", { get: function editableInputs(elem) DOM.editableInputs }),
+    escapeHTML: deprecated("DOM.escapeHTML", { get: function escapeHTML(elem) DOM.escapeHTML }),
+    evaluateXPath: deprecated("DOM.XPath",
+        function evaluateXPath(path, elem, asIterator) DOM.XPath(path, elem || util.activeWindow.content.document, asIterator)),
+    isVisible: deprecated("DOM#isVisible", function isVisible(elem) DOM(elem).isVisible),
+    makeXPath: deprecated("DOM.makeXPath", { get: function makeXPath(elem) DOM.makeXPath }),
+    namespaces: deprecated("DOM.namespaces", { get: function namespaces(elem) DOM.namespaces }),
+    namespaceNames: deprecated("DOM.namespaceNames", { get: function namespaceNames(elem) DOM.namespaceNames }),
+    parseForm: deprecated("DOM#formData", function parseForm(elem) values(DOM(elem).formData).toArray()),
+    scrollIntoView: deprecated("DOM#scrollIntoView", function scrollIntoView(elem, alignWithTop) DOM(elem).scrollIntoView(alignWithTop)),
+    validateMatcher: deprecated("DOM.validateMatcher", { get: function validateMatcher() DOM.validateMatcher }),
 
-        return update(
-            function matcher(node) {
-                if (matcher.xpath)
-                    for (let elem in util.evaluateXPath(matcher.xpath, node))
-                        yield elem;
-
-                if (matcher.css)
-                    for (let [, elem] in iter(node.querySelectorAll(matcher.css)))
-                        yield elem;
-            }, {
-                css: css.join(", "),
-                xpath: xpath.join(" | ")
-            });
-    },
-
-    /**
-     * Validates a list as input for {@link #compileMatcher}. Returns
-     * true if and only if every element of the list is a valid XPath or
-     * CSS selector.
-     *
-     * @param {[string]} list The list of patterns to test
-     * @returns {boolean} True when the patterns are all valid.
-     */
-    validateMatcher: function validateMatcher(list) {
-        let evaluator = services.XPathEvaluator();
-        let node = services.XMLDocument();
-        return this.testValues(list, function (value) {
-            if (/^xpath:/.test(value))
-                evaluator.createExpression(value.substr(6), util.evaluateXPath.resolver);
-            else
-                node.querySelector(value);
-            return true;
-        });
-    },
-
-    /**
-     * Returns an object representing a Node's computed CSS style.
-     *
-     * @param {Node} node
-     * @returns {Object}
-     */
-    computedStyle: function computedStyle(node) {
-        while (!(node instanceof Ci.nsIDOMElement) && node.parentNode)
-            node = node.parentNode;
-        try {
-            var res = node.ownerDocument.defaultView.getComputedStyle(node, null);
-        }
-        catch (e) {}
-        if (res == null) {
-            util.dumpStack(_("error.nullComputedStyle", node));
-            Cu.reportError(Error(_("error.nullComputedStyle", node)));
-            return {};
-        }
-        return res;
-    },
+    chromePackages: deprecated("config.chromePackages", { get: function chromePackages() config.chromePackages }),
+    haveGecko: deprecated("config.haveGecko", { get: function haveGecko() config.closure.haveGecko }),
+    OS: deprecated("config.OS", { get: function OS() config.OS }),
 
     /**
      * Converts any arbitrary string into an URI object. Returns null on
@@ -614,44 +510,6 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
         pattern.replace(/\\(.)/, function (m0, m1) chars.indexOf(m1) >= 0 ? m1 : m0),
 
     /**
-     * Converts a given DOM Node, Range, or Selection to a string. If
-     * *html* is true, the output is HTML, otherwise it is presentation
-     * text.
-     *
-     * @param {nsIDOMNode | nsIDOMRange | nsISelection} node The node to
-     *      stringify.
-     * @param {boolean} html Whether the output should be HTML rather
-     *      than presentation text.
-     */
-    domToString: function (node, html) {
-        if (node instanceof Ci.nsISelection && node.isCollapsed)
-            return "";
-
-        if (node instanceof Ci.nsIDOMNode) {
-            let range = node.ownerDocument.createRange();
-            range.selectNode(node);
-            node = range;
-        }
-        let doc = (node.getRangeAt ? node.getRangeAt(0) : node).startContainer;
-        doc = doc.ownerDocument || doc;
-
-        let encoder = services.HtmlEncoder();
-        encoder.init(doc, "text/unicode", encoder.OutputRaw|encoder.OutputPreformatted);
-        if (node instanceof Ci.nsISelection)
-            encoder.setSelection(node);
-        else if (node instanceof Ci.nsIDOMRange)
-            encoder.setRange(node);
-
-        let str = services.String(encoder.encodeToString());
-        if (html)
-            return str.data;
-
-        let [result, length] = [{}, {}];
-        services.HtmlConverter().convert("text/html", str, str.data.length*2, "text/unicode", result, length);
-        return result.value.QueryInterface(Ci.nsISupportsString).data;
-    },
-
-    /**
      * Prints a message to the console. If *msg* is an object it is pretty
      * printed.
      *
@@ -688,25 +546,6 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
     },
 
     /**
-     * The set of input element type attribute values that mark the element as
-     * an editable field.
-     */
-    editableInputs: Set(["date", "datetime", "datetime-local", "email", "file",
-                         "month", "number", "password", "range", "search",
-                         "tel", "text", "time", "url", "week"]),
-
-    /**
-     * Converts HTML special characters in *str* to the equivalent HTML
-     * entities.
-     *
-     * @param {string} str
-     * @returns {string}
-     */
-    escapeHTML: function escapeHTML(str) {
-        return str.replace(/&/g, "&amp;").replace(/</g, "&lt;");
-    },
-
-    /**
      * Escapes quotes, newline and tab characters in *str*. The returned string
      * is delimited by *delimiter* or " if *delimiter* is not specified.
      * {@see String#quote}.
@@ -721,92 +560,6 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
         return delimiter + str.replace(/([\\'"])/g, "\\$1").replace("\n", "\\n", "g").replace("\t", "\\t", "g") + delimiter;
     },
 
-    /**
-     * Evaluates an XPath expression in the current or provided
-     * document. It provides the xhtml, xhtml2 and dactyl XML
-     * namespaces. The result may be used as an iterator.
-     *
-     * @param {string} expression The XPath expression to evaluate.
-     * @param {Node} elem The context element.
-     * @default The current document.
-     * @param {boolean} asIterator Whether to return the results as an
-     *     XPath iterator.
-     * @returns {Object} Iterable result of the evaluation.
-     */
-    evaluateXPath: update(
-        function evaluateXPath(expression, elem, asIterator) {
-            try {
-                if (!elem)
-                    elem = util.activeWindow.content.document;
-                let doc = elem.ownerDocument || elem;
-                if (isArray(expression))
-                    expression = util.makeXPath(expression);
-
-                let result = doc.evaluate(expression, elem,
-                    evaluateXPath.resolver,
-                    asIterator ? Ci.nsIDOMXPathResult.ORDERED_NODE_ITERATOR_TYPE : Ci.nsIDOMXPathResult.ORDERED_NODE_SNAPSHOT_TYPE,
-                    null
-                );
-
-                return Object.create(result, {
-                    __iterator__: {
-                        value: asIterator ? function () { let elem; while ((elem = this.iterateNext())) yield elem; }
-                                          : function () { for (let i = 0; i < this.snapshotLength; i++) yield this.snapshotItem(i); }
-                    }
-                });
-            }
-            catch (e) {
-                throw e.stack ? e : Error(e);
-            }
-        },
-        {
-            resolver: function lookupNamespaceURI(prefix) (util.namespaces[prefix] || null)
-        }),
-
-    /**
-     * Generates an XPath expression for the given element.
-     *
-     * @param {Element} elem The element for which to generate an XPath.
-     * @returns {string}
-     */
-    generateXPath: function generateXPath(elem) {
-        function quote(val) "'" + val.replace(/[\\']/g, "\\$&") + "'";
-
-        let res = [];
-        let doc = elem.ownerDocument;
-        for (;; elem = elem.parentNode) {
-            if (!(elem instanceof Ci.nsIDOMElement))
-                res.push("");
-            else if (elem.id)
-                res.push("id(" + quote(elem.id) + ")");
-            else {
-                let name = elem.localName;
-                if (elem.namespaceURI && (elem.namespaceURI != XHTML || doc.xmlVersion))
-                    if (elem.namespaceURI in this.namespaceNames)
-                        name = this.namespaceNames[elem.namespaceURI] + ":" + name;
-                    else
-                        name = "*[local-name()=" + quote(name) + " and namespace-uri()=" + quote(elem.namespaceURI) + "]";
-
-                res.push(name + "[" + (1 + iter(this.evaluateXPath("./" + name, elem.parentNode)).indexOf(elem)) + "]");
-                continue;
-            }
-            break;
-        }
-
-        return res.reverse().join("/");
-    },
-
-    namespaces: {
-        xul: XUL.uri,
-        xhtml: XHTML.uri,
-        html: XHTML.uri,
-        xhtml2: "http://www.w3.org/2002/06/xhtml2",
-        dactyl: NS.uri
-    },
-
-    namespaceNames: Class.memoize(function ()
-        iter(this.namespaces).map(function ([k, v]) [v, k]).toObject()),
-
     extend: function extend(dest) {
         Array.slice(arguments, 1).filter(util.identity).forEach(function (src) {
             for (let [k, v] in Iterator(src)) {
@@ -925,15 +678,6 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
     },
 
     /**
-     * Returns true if the current Gecko runtime is of the given version
-     * or greater.
-     *
-     * @param {string} ver The required version.
-     * @returns {boolean}
-     */
-    haveGecko: function (ver) services.versionCompare.compare(services.runtime.platformVersion, ver) >= 0,
-
-    /**
      * Sends a synchronous or asynchronous HTTP request to *url* and returns
      * the XMLHttpRequest object. If *callback* is specified the request is
      * asynchronous and the *callback* is invoked with the object as its
@@ -1017,24 +761,6 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
      */
     isDomainURL: function isDomainURL(url, domain) util.isSubdomain(util.getHost(url), domain),
 
-    /** Dactyl's notion of the current operating system platform. */
-    OS: memoize({
-        _arch: services.runtime.OS,
-        /**
-         * @property {string} The normalised name of the OS. This is one of
-         *     "Windows", "Mac OS X" or "Unix".
-         */
-        get name() this.isWindows ? "Windows" : this.isMacOSX ? "Mac OS X" : "Unix",
-        /** @property {boolean} True if the OS is Windows. */
-        get isWindows() this._arch == "WINNT",
-        /** @property {boolean} True if the OS is Mac OS X. */
-        get isMacOSX() this._arch == "Darwin",
-        /** @property {boolean} True if the OS is some other *nix variant. */
-        get isUnix() !this.isWindows && !this.isMacOSX,
-        /** @property {RegExp} A RegExp which matches illegal characters in path components. */
-        get illegalCharacters() this.isWindows ? /[<>:"/\\|?*\x00-\x1f]/g : /\//g
-    }),
-
     /**
      * Returns true if *host* is a subdomain of *domain*.
      *
@@ -1050,17 +776,6 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
     },
 
     /**
-     * Returns true if the given DOM node is currently visible.
-     *
-     * @param {Node} node
-     * @returns {boolean}
-     */
-    isVisible: function (node) {
-        let style = util.computedStyle(node);
-        return style.visibility == "visible" && style.display != "none";
-    },
-
-    /**
      * Iterates over all currently open documents, including all
      * top-level window and sub-frames thereof.
      */
@@ -1110,20 +825,6 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
     },
 
     /**
-     * Returns an XPath union expression constructed from the specified node
-     * tests. An expression is built with node tests for both the null and
-     * XHTML namespaces. See {@link Buffer#evaluateXPath}.
-     *
-     * @param nodes {Array(string)}
-     * @returns {string}
-     */
-    makeXPath: function makeXPath(nodes) {
-        return array(nodes).map(util.debrace).flatten()
-                           .map(function (node) /^[a-z]+:/.test(node) ? node : [node, "xhtml:" + node]).flatten()
-                           .map(function (node) "//" + node).join(" | ");
-    },
-
-    /**
      * Creates a DTD fragment from the given object. Each property of
      * the object is converted to an ENTITY declaration. SGML special
      * characters other than ' and % are left intact.
@@ -1150,7 +851,6 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
      * @param {string} uri
      * @returns {nsIURI}
      */
-    // FIXME: createURI needed too?
     newURI: function newURI(uri, charset, base) this.withProperErrors("newURI", services.io, uri, charset, base),
 
     /**
@@ -1181,43 +881,12 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
         if (!isObject(object))
             return String(object);
 
-        function namespaced(node) {
-            var ns = util.namespaceNames[node.namespaceURI] || /^(?:(.*?):)?/.exec(node.name)[0];
-            if (!ns)
-                return node.localName;
-            if (color)
-                return <><span highlight="HelpXMLNamespace">{ns}</span>{node.localName}</>
-            return ns + ":" + node.localName;
-        }
-
         if (object instanceof Ci.nsIDOMElement) {
             let elem = object;
             if (elem.nodeType == elem.TEXT_NODE)
                 return elem.data;
 
-            try {
-                let hasChildren = elem.firstChild && (!/^\s*$/.test(elem.firstChild) || elem.firstChild.nextSibling)
-                if (color)
-                    return <span highlight="HelpXMLBlock"><span highlight="HelpXMLTagStart">&lt;{
-                            namespaced(elem)} {
-                                template.map(array.iterValues(elem.attributes),
-                                    function (attr)
-                                        <span highlight="HelpXMLAttribute">{namespaced(attr)}</span> +
-                                        <span highlight="HelpXMLString">{attr.value}</span>,
-                                    <> </>)
-                            }{ !hasChildren ? "/>" : ">"
-                        }</span>{ !hasChildren ? "" : <>...</> +
-                            <span highlight="HtmlTagEnd">&lt;{namespaced(elem)}></span>
-                    }</span>;
-
-                let tag = "<" + [namespaced(elem)].concat(
-                    [namespaced(a) + "=" + template.highlight(a.value, true)
-                     for ([i, a] in array.iterItems(elem.attributes))]).join(" ");
-                return tag + (!hasChildren ? "/>" : ">...</" + namespaced(elem) + ">");
-            }
-            catch (e) {
-                return {}.toString.call(elem);
-            }
+            return DOM(elem).repr(color);
         }
 
         try { // for window.JSON
@@ -1487,68 +1156,6 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
     },
 
     /**
-     * Parses the fields of a form and returns a URL/POST-data pair
-     * that is the equivalent of submitting the form.
-     *
-     * @param {nsINode} field One of the fields of the given form.
-     * @returns {array}
-     */
-    // Nuances gleaned from browser.jar/content/browser/browser.js
-    parseForm: function parseForm(field) {
-        function encode(name, value, param) {
-            param = param ? "%s" : "";
-            if (post)
-                return name + "=" + encodeComponent(value + param);
-            return encodeComponent(name) + "=" + encodeComponent(value) + param;
-        }
-
-        let form = field.form;
-        let doc = form.ownerDocument;
-
-        let charset = doc.characterSet;
-        let converter = services.CharsetConv(charset);
-        for each (let cs in form.acceptCharset.split(/\s*,\s*|\s+/)) {
-            let c = services.CharsetConv(cs);
-            if (c) {
-                converter = services.CharsetConv(cs);
-                charset = cs;
-            }
-        }
-
-        let uri = util.newURI(doc.baseURI.replace(/\?.*/, ""), charset);
-        let url = util.newURI(form.action, charset, uri).spec;
-
-        let post = form.method.toUpperCase() == "POST";
-
-        let encodeComponent = encodeURIComponent;
-        if (charset !== "UTF-8")
-            encodeComponent = function encodeComponent(str)
-                escape(converter.ConvertFromUnicode(str) + converter.Finish());
-
-        let elems = [];
-        if (field instanceof Ci.nsIDOMHTMLInputElement && field.type == "submit")
-            elems.push(encode(field.name, field.value));
-
-        for (let [, elem] in iter(form.elements))
-            if (elem.name && !elem.disabled) {
-                if (Set.has(util.editableInputs, elem.type)
-                        || /^(?:hidden|textarea)$/.test(elem.type)
-                        || elem.type == "submit" && elem == field
-                        || elem.checked && /^(?:checkbox|radio)$/.test(elem.type))
-                    elems.push(encode(elem.name, elem.value, elem === field));
-                else if (elem instanceof Ci.nsIDOMHTMLSelectElement) {
-                    for (let [, opt] in Iterator(elem.options))
-                        if (opt.selected)
-                            elems.push(encode(elem.name, opt.value));
-                }
-            }
-
-        if (post)
-            return [url, elems.join('&'), charset, elems];
-        return [url + "?" + elems.join('&'), null, charset, elems];
-    },
-
-    /**
      * A generator that returns the values between *start* and *end*, in *step*
      * increments.
      *
@@ -1790,19 +1397,6 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
     },
 
     /**
-     * Scrolls an element into view if and only if it's not already
-     * fully visible.
-     *
-     * @param {Node} elem The element to make visible.
-     */
-    scrollIntoView: function scrollIntoView(elem, alignWithTop) {
-        let win = elem.ownerDocument.defaultView;
-        let rect = elem.getBoundingClientRect();
-        if (!(rect && rect.bottom <= win.innerHeight && rect.top >= 0 && rect.left < win.innerWidth && rect.right > 0))
-            elem.scrollIntoView(arguments.length > 1 ? alignWithTop : Math.abs(rect.top) < Math.abs(win.innerHeight - rect.bottom));
-    },
-
-    /**
      * Returns the selection controller for the given window.
      *
      * @param {Window} window
@@ -1814,6 +1408,12 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
            .QueryInterface(Ci.nsISelectionController),
 
     /**
+     * Escapes a string against shell meta-characters and argument
+     * separators.
+     */
+    shellEscape: function shellEscape(str) '"' + String.replace(str, /[\\"$]/g, "\\$&") + '"',
+
+    /**
      * Suspend execution for at least *delay* milliseconds. Functions by
      * yielding execution to the next item in the main event queue, and
      * so may lead to unexpected call graphs, and long delays if another
@@ -2139,6 +1739,16 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
     Array: array
 });
 
+
+/**
+ * @class
+ *
+ * A jQuery-inspired DOM utility framework.
+ *
+ * Please note that while this currently implements an Array-like
+ * interface, this is *not a defined interface* and is very likely to
+ * change in the near future.
+ */
 var DOM = Class("DOM", {
     init: function init(val, context) {
         let self;
@@ -2153,12 +1763,15 @@ var DOM = Class("DOM", {
         if (val == null)
             ;
         else if (typeof val == "xml")
-            this[length++] = util.xmlToDom(val, context);
-        else if (val instanceof Ci.nsIDOMNode)
+            this[length++] = util.xmlToDom(val, context, this.nodes);
+        else if (val instanceof Ci.nsIDOMNode || val instanceof Ci.nsIDOMWindow)
             this[length++] = val;
         else if ("length" in val)
             for (let i = 0; i < val.length; i++)
                 this[length++] = val[i];
+        else if ("__iterator__" in val)
+            for (let elem in val)
+                this[length++] = elem;
 
         this.length = length;
         return self || this;
@@ -2171,6 +1784,8 @@ var DOM = Class("DOM", {
 
     Empty: function Empty() this.constructor(null, this.document),
 
+    nodes: Class.memoize(function () ({})),
+
     get items() {
         for (let i = 0; i < this.length; i++)
             yield this.eq(i);
@@ -2234,10 +1849,10 @@ var DOM = Class("DOM", {
 
         if (callable(val))
             return this.each(function (elem, i) {
-                fn.call(this, munge(val.call(this, elem, i)), elem, i);
+                util.withProperErrors(fn, this, munge(val.call(this, elem, i)), elem, i);
             }, self || this);
 
-        fn.call(self || this, munge(val), this[0], 0);
+        util.withProperErrors(fn, self || this, munge(val), this[0], 0);
         return this;
     },
 
@@ -2276,8 +1891,16 @@ var DOM = Class("DOM", {
         let res = this.Empty();
 
         this.each(function (elem) {
-            while((elem = fn.call(this, elem)) instanceof Ci.nsIDOMElement)
-                res[res.length++] = elem;
+            while(true) {
+                elem = fn.call(this, elem)
+                if (elem instanceof Ci.nsIDOMElement)
+                    res[res.length++] = elem;
+                else if (elem && "length" in elem)
+                    for (let i = 0; i < tmp.length; i++)
+                        res[res.length++] = tmp[j];
+                else
+                    break;
+            }
         }, self || this);
         return res;
     },
@@ -2288,10 +1911,10 @@ var DOM = Class("DOM", {
 
         for (let i = 0; i < this.length; i++) {
             let tmp = fn.call(self || update(obj, [this[i]]), this[i], i);
-            if ("length" in tmp)
+            if (tmp && "length" in tmp)
                 for (let j = 0; j < tmp.length; j++)
                     res[res.length++] = tmp[j];
-            else
+            else if (tmp !== undefined)
                 res[res.length++] = tmp;
         }
 
@@ -2311,6 +1934,15 @@ var DOM = Class("DOM", {
 
     get parent() this.map(function (elem) elem.parentNode, this),
 
+    get offsetParent() this.map(function (elem) {
+        do {
+            var parent = elem.offsetParent;
+            if (parent instanceof Ci.nsIDOMElement && DOM(parent).position != "static")
+                return parent;
+        }
+        while (parent);
+    }, this),
+
     get ancestors() this.all(function (elem) elem.parentNode),
 
     get children() this.map(function (elem) Array.filter(elem.childNodes,
@@ -2354,6 +1986,7 @@ var DOM = Class("DOM", {
         has: function has(hl) ~this.list.indexOf(hl),
 
         add: function add(hl) self.each(function () {
+            highlight.loaded[hl] = true;
             this.attrNS(NS, "highlight",
                         array.uniq(this.highlight.list.concat(hl)).join(" "));
         }),
@@ -2371,7 +2004,213 @@ var DOM = Class("DOM", {
 
     get rect() this[0].getBoundingClientRect(),
 
-    get style() util.computedStyle(this[0]),
+    get viewport() {
+        let r = this.rect;
+        return {
+            width: this[0].clientWidth,
+            height: this[0].clientHeight,
+            top: r.top + this[0].clientTop,
+            get bottom() this.top + this.height,
+            left: r.left + this[0].clientLeft,
+            get right() this.left + this.width
+        }
+    },
+
+    /**
+     * Returns true if the given DOM node is currently visible.
+     * @returns {boolean}
+     */
+    get isVisible() {
+        let style = this.style;
+        return style.visibility == "visible" && style.display != "none";
+    },
+
+    get editor() {
+        this[0] instanceof Ci.nsIDOMNSEditableElement;
+        if (this[0].editor instanceof Ci.nsIEditor)
+            return this[0].editor;
+
+        try {
+            return this[0].QueryInterface(Ci.nsIInterfaceRequestor).getInterface(Ci.nsIWebNavigation)
+                          .QueryInterface(Ci.nsIInterfaceRequestor).getInterface(Ci.nsIEditingSession)
+                          .getEditorForWindow(this[0]);
+        }
+        catch (e) {}
+
+        return null;
+    },
+
+    get isEditable() !!this.editor,
+
+    get isInput() this[0] instanceof Ci.nsIDOMHTMLInputElement && this.isEditable,
+
+    /**
+     * Returns an object representing a Node's computed CSS style.
+     * @returns {Object}
+     */
+    get style() {
+        let node = this[0];
+        while (!(node instanceof Ci.nsIDOMElement) && node.parentNode)
+            node = node.parentNode;
+
+        try {
+            var res = node.ownerDocument.defaultView.getComputedStyle(node, null);
+        }
+        catch (e) {}
+
+        if (res == null) {
+            util.dumpStack(_("error.nullComputedStyle", node));
+            Cu.reportError(Error(_("error.nullComputedStyle", node)));
+            return {};
+        }
+        return res;
+    },
+
+    /**
+     * Parses the fields of a form and returns a URL/POST-data pair
+     * that is the equivalent of submitting the form.
+     *
+     * @returns {object} An object with the following elements:
+     *      url: The URL the form points to.
+     *      postData: A string containing URL-encoded post data, if this
+     *                form is to be POSTed
+     *      charset: The character set of the GET or POST data.
+     *      elements: The key=value pairs used to generate query information.
+     */
+    // Nuances gleaned from browser.jar/content/browser/browser.js
+    get formData() {
+        function encode(name, value, param) {
+            param = param ? "%s" : "";
+            if (post)
+                return name + "=" + encodeComponent(value + param);
+            return encodeComponent(name) + "=" + encodeComponent(value) + param;
+        }
+
+        let field = this[0];
+        let form = field.form;
+        let doc = form.ownerDocument;
+
+        let charset = doc.characterSet;
+        let converter = services.CharsetConv(charset);
+        for each (let cs in form.acceptCharset.split(/\s*,\s*|\s+/)) {
+            let c = services.CharsetConv(cs);
+            if (c) {
+                converter = services.CharsetConv(cs);
+                charset = cs;
+            }
+        }
+
+        let uri = util.newURI(doc.baseURI.replace(/\?.*/, ""), charset);
+        let url = util.newURI(form.action, charset, uri).spec;
+
+        let post = form.method.toUpperCase() == "POST";
+
+        let encodeComponent = encodeURIComponent;
+        if (charset !== "UTF-8")
+            encodeComponent = function encodeComponent(str)
+                escape(converter.ConvertFromUnicode(str) + converter.Finish());
+
+        let elems = [];
+        if (field instanceof Ci.nsIDOMHTMLInputElement && field.type == "submit")
+            elems.push(encode(field.name, field.value));
+
+        for (let [, elem] in iter(form.elements))
+            if (elem.name && !elem.disabled) {
+                if (DOM(elem).isInput
+                        || /^(?:hidden|textarea)$/.test(elem.type)
+                        || elem.type == "submit" && elem == field
+                        || elem.checked && /^(?:checkbox|radio)$/.test(elem.type))
+                    elems.push(encode(elem.name, elem.value, elem === field));
+                else if (elem instanceof Ci.nsIDOMHTMLSelectElement) {
+                    for (let [, opt] in Iterator(elem.options))
+                        if (opt.selected)
+                            elems.push(encode(elem.name, opt.value));
+                }
+            }
+
+        if (post)
+            return { url: url, postData: elems.join('&'), charset: charset, elements: elems };
+        return { url: url + "?" + elems.join('&'), postData: null, charset: charset, elements: elems };
+    },
+
+    /**
+     * Generates an XPath expression for the given element.
+     *
+     * @returns {string}
+     */
+    get xpath() {
+        function quote(val) "'" + val.replace(/[\\']/g, "\\$&") + "'";
+
+        let res = [];
+        let doc = this.document;
+        for (let elem = this[0];; elem = elem.parentNode) {
+            if (!(elem instanceof Ci.nsIDOMElement))
+                res.push("");
+            else if (elem.id)
+                res.push("id(" + quote(elem.id) + ")");
+            else {
+                let name = elem.localName;
+                if (elem.namespaceURI && (elem.namespaceURI != XHTML || doc.xmlVersion))
+                    if (elem.namespaceURI in DOM.namespaceNames)
+                        name = DOM.namespaceNames[elem.namespaceURI] + ":" + name;
+                    else
+                        name = "*[local-name()=" + quote(name) + " and namespace-uri()=" + quote(elem.namespaceURI) + "]";
+
+                res.push(name + "[" + (1 + iter(DOM.XPath("./" + name, elem.parentNode)).indexOf(elem)) + "]");
+                continue;
+            }
+            break;
+        }
+
+        return res.reverse().join("/");
+    },
+
+    /**
+     * Returns a string or XML representation of this node.
+     *
+     * @param {boolean} color If true, return a colored, XML
+     *  representation of this node.
+     */
+    repr: function repr(color) {
+        function namespaced(node) {
+            var ns = DOM.namespaceNames[node.namespaceURI] || /^(?:(.*?):)?/.exec(node.name)[0];
+            if (!ns)
+                return node.localName;
+            if (color)
+                return <><span highlight="HelpXMLNamespace">{ns}</span>{node.localName}</>
+            return ns + ":" + node.localName;
+        }
+
+        let res = [];
+        this.each(function (elem) {
+            try {
+                let hasChildren = elem.firstChild && (!/^\s*$/.test(elem.firstChild) || elem.firstChild.nextSibling)
+                if (color)
+                    res.push(<span highlight="HelpXMLBlock"><span highlight="HelpXMLTagStart">&lt;{
+                            namespaced(elem)} {
+                                template.map(array.iterValues(elem.attributes),
+                                    function (attr)
+                                        <span highlight="HelpXMLAttribute">{namespaced(attr)}</span> +
+                                        <span highlight="HelpXMLString">{attr.value}</span>,
+                                    <> </>)
+                            }{ !hasChildren ? "/>" : ">"
+                        }</span>{ !hasChildren ? "" : <>...</> +
+                            <span highlight="HtmlTagEnd">&lt;{namespaced(elem)}></span>
+                    }</span>);
+                else {
+                    let tag = "<" + [namespaced(elem)].concat(
+                        [namespaced(a) + "=" + template.highlight(a.value, true)
+                         for ([i, a] in array.iterItems(elem.attributes))]).join(" ");
+
+                    res.push(tag + (!hasChildren ? "/>" : ">...</" + namespaced(elem) + ">"));
+                }
+            }
+            catch (e) {
+                res.push({}.toString.call(elem));
+            }
+        }, this);
+        return template.map(res, util.identity, <>,</>);
+    },
 
     attr: function attr(key, val) {
         return this.attrNS("", key, val);
@@ -2574,7 +2413,32 @@ var DOM = Class("DOM", {
         if (callable(arg))
             return this.listen("blur", arg, extra);
         return this.each(function (elem) { elem.blur(); }, this);
-    }
+    },
+
+    /**
+     * Scrolls an element into view if and only if it's not already
+     * fully visible.
+     */
+    scrollIntoView: function scrollIntoView(alignWithTop) {
+        return this.each(function (elem) {
+            let rect = this.rect;
+
+            let force = false;
+            if (rect)
+                for (let parent in this.ancestors.items) {
+                    let isect = util.intersection(rect, parent.viewport);
+                    force = isect.width != rect.width || isect.height != rect.height;
+                    if (force)
+                        break;
+                }
+
+            let win = this.document.defaultView;
+
+            if (force || !(rect && rect.bottom <= win.innerHeight && rect.top >= 0 && rect.left < win.innerWidth && rect.right > 0))
+                elem.scrollIntoView(arguments.length ? alignWithTop
+                                                     : Math.abs(rect.top) < Math.abs(win.innerHeight - rect.bottom));
+        });
+    },
 }, {
     /**
      * Creates an actual event from a pseudo-event object.
@@ -2643,7 +2507,7 @@ var DOM = Class("DOM", {
          * @param {Event} event The event to dispatch.
          */
         dispatch: Class.memoize(function ()
-            util.haveGecko("2b")
+            config.haveGecko("2b")
                 ? function dispatch(target, event, extra) {
                     try {
                         this.feedingEvent = extra;
@@ -2674,7 +2538,184 @@ var DOM = Class("DOM", {
                         this.feedingEvent = null;
                     }
                 })
-    })
+    }),
+
+    /**
+     * The set of input element type attribute values that mark the element as
+     * an editable field.
+     */
+    editableInputs: Set(["date", "datetime", "datetime-local", "email", "file",
+                         "month", "number", "password", "range", "search",
+                         "tel", "text", "time", "url", "week"]),
+
+    /**
+     * Converts a given DOM Node, Range, or Selection to a string. If
+     * *html* is true, the output is HTML, otherwise it is presentation
+     * text.
+     *
+     * @param {nsIDOMNode | nsIDOMRange | nsISelection} node The node to
+     *      stringify.
+     * @param {boolean} html Whether the output should be HTML rather
+     *      than presentation text.
+     */
+    stringify: function stringify(node, html) {
+        if (node instanceof Ci.nsISelection && node.isCollapsed)
+            return "";
+
+        if (node instanceof Ci.nsIDOMNode) {
+            let range = node.ownerDocument.createRange();
+            range.selectNode(node);
+            node = range;
+        }
+        let doc = (node.getRangeAt ? node.getRangeAt(0) : node).startContainer;
+        doc = doc.ownerDocument || doc;
+
+        let encoder = services.HtmlEncoder();
+        encoder.init(doc, "text/unicode", encoder.OutputRaw|encoder.OutputPreformatted);
+        if (node instanceof Ci.nsISelection)
+            encoder.setSelection(node);
+        else if (node instanceof Ci.nsIDOMRange)
+            encoder.setRange(node);
+
+        let str = services.String(encoder.encodeToString());
+        if (html)
+            return str.data;
+
+        let [result, length] = [{}, {}];
+        services.HtmlConverter().convert("text/html", str, str.data.length*2, "text/unicode", result, length);
+        return result.value.QueryInterface(Ci.nsISupportsString).data;
+    },
+
+    /**
+     * Compiles a CSS spec and XPath pattern matcher based on the given
+     * list. List elements prefixed with "xpath:" are parsed as XPath
+     * patterns, while other elements are parsed as CSS specs. The
+     * returned function will, given a node, return an iterator of all
+     * descendants of that node which match the given specs.
+     *
+     * @param {[string]} list The list of patterns to match.
+     * @returns {function(Node)}
+     */
+    compileMatcher: function compileMatcher(list) {
+        let xpath = [], css = [];
+        for (let elem in values(list))
+            if (/^xpath:/.test(elem))
+                xpath.push(elem.substr(6));
+            else
+                css.push(elem);
+
+        return update(
+            function matcher(node) {
+                if (matcher.xpath)
+                    for (let elem in DOM.XPath(matcher.xpath, node))
+                        yield elem;
+
+                if (matcher.css)
+                    for (let [, elem] in iter(node.querySelectorAll(matcher.css)))
+                        yield elem;
+            }, {
+                css: css.join(", "),
+                xpath: xpath.join(" | ")
+            });
+    },
+
+    /**
+     * Validates a list as input for {@link #compileMatcher}. Returns
+     * true if and only if every element of the list is a valid XPath or
+     * CSS selector.
+     *
+     * @param {[string]} list The list of patterns to test
+     * @returns {boolean} True when the patterns are all valid.
+     */
+    validateMatcher: function validateMatcher(list) {
+        let evaluator = services.XPathEvaluator();
+        let node = services.XMLDocument();
+        return this.testValues(list, function (value) {
+            if (/^xpath:/.test(value))
+                evaluator.createExpression(value.substr(6), DOM.XPath.resolver);
+            else
+                node.querySelector(value);
+            return true;
+        });
+    },
+
+    /**
+     * Converts HTML special characters in *str* to the equivalent HTML
+     * entities.
+     *
+     * @param {string} str
+     * @returns {string}
+     */
+    escapeHTML: function escapeHTML(str) {
+        let map = { "'": "&apos;", '"': "&quot;", "%": "&#x25;", "&": "&amp;", "<": "&lt;", ">": "&gt;" };
+        return str.replace(/['"&<>]/g, function (m) map[m]);
+    },
+
+
+    /**
+     * Evaluates an XPath expression in the current or provided
+     * document. It provides the xhtml, xhtml2 and dactyl XML
+     * namespaces. The result may be used as an iterator.
+     *
+     * @param {string} expression The XPath expression to evaluate.
+     * @param {Node} elem The context element.
+     * @param {boolean} asIterator Whether to return the results as an
+     *     XPath iterator.
+     * @returns {Object} Iterable result of the evaluation.
+     */
+    XPath: update(
+        function XPath(expression, elem, asIterator) {
+            try {
+                let doc = elem.ownerDocument || elem;
+
+                if (isArray(expression))
+                    expression = DOM.makeXPath(expression);
+
+                let result = doc.evaluate(expression, elem,
+                    XPath.resolver,
+                    asIterator ? Ci.nsIDOMXPathResult.ORDERED_NODE_ITERATOR_TYPE : Ci.nsIDOMXPathResult.ORDERED_NODE_SNAPSHOT_TYPE,
+                    null
+                );
+
+                return Object.create(result, {
+                    __iterator__: {
+                        value: asIterator ? function () { let elem; while ((elem = this.iterateNext())) yield elem; }
+                                          : function () { for (let i = 0; i < this.snapshotLength; i++) yield this.snapshotItem(i); }
+                    }
+                });
+            }
+            catch (e) {
+                throw e.stack ? e : Error(e);
+            }
+        },
+        {
+            resolver: function lookupNamespaceURI(prefix) (DOM.namespaces[prefix] || null)
+        }),
+
+    /**
+     * Returns an XPath union expression constructed from the specified node
+     * tests. An expression is built with node tests for both the null and
+     * XHTML namespaces. See {@link DOM.XPath}.
+     *
+     * @param nodes {Array(string)}
+     * @returns {string}
+     */
+    makeXPath: function makeXPath(nodes) {
+        return array(nodes).map(util.debrace).flatten()
+                           .map(function (node) /^[a-z]+:/.test(node) ? node : [node, "xhtml:" + node]).flatten()
+                           .map(function (node) "//" + node).join(" | ");
+    },
+
+    namespaces: {
+        xul: XUL.uri,
+        xhtml: XHTML.uri,
+        html: XHTML.uri,
+        xhtml2: "http://www.w3.org/2002/06/xhtml2",
+        dactyl: NS.uri
+    },
+
+    namespaceNames: Class.memoize(function ()
+        iter(this.namespaces).map(function ([k, v]) [v, k]).toObject()),
 });
 
 Object.keys(DOM.Event.types).forEach(function (event) {