diff -r 378495e669f9 toolkit/Makefile.in
--- a/toolkit/Makefile.in	Sat Jun 28 03:55:30 2008 -0400
+++ b/toolkit/Makefile.in	Tue Jul 01 15:36:38 2008 -0400
@@ -49,6 +49,7 @@ DIRS	= \
 		obsolete \
 		profile \
 		themes \
+		spatial-navigation \
 		$(NULL)
 
 ifneq (,$(filter gtk2,$(MOZ_WIDGET_TOOLKIT)))
diff -r 378495e669f9 toolkit/spatial-navigation/Makefile.in
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/spatial-navigation/Makefile.in	Tue Jul 01 15:36:38 2008 -0400
@@ -0,0 +1,52 @@
+# ***** BEGIN LICENSE BLOCK *****
+# Version: MPL 1.1/GPL 2.0/LGPL 2.1
+#
+# The contents of this file are subject to the Mozilla Public License Version
+# 1.1 (the "License"); you may not use this file except in compliance with
+# the License. You may obtain a copy of the License at
+# http://www.mozilla.org/MPL/
+#
+# Software distributed under the License is distributed on an "AS IS" basis,
+# WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+# for the specific language governing rights and limitations under the
+# License.
+#
+# The Original Code is mozilla.org build system.
+#
+# The Initial Developer of the Original Code is Mozilla Corporation
+# Portions created by the Initial Developer are Copyright (C) 2008
+# the Initial Developer. All Rights Reserved.
+#
+# Contributor(s):
+#  Doug Turner <dougt@meer.net>
+#
+# Alternatively, the contents of this file may be used under the terms of
+# either the GNU General Public License Version 2 or later (the "GPL"), or
+# the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+# in which case the provisions of the GPL or the LGPL are applicable instead
+# of those above. If you wish to allow use of your version of this file only
+# under the terms of either the GPL or the LGPL, and not to allow others to
+# use your version of this file under the terms of the MPL, indicate your
+# decision by deleting the provisions above and replace them with the notice
+# and other provisions required by the GPL or the LGPL. If you do not delete
+# the provisions above, a recipient may use your version of this file under
+# the terms of any one of the MPL, the GPL or the LGPL.
+#
+# ***** END LICENSE BLOCK *****
+
+DEPTH		= ../..
+topsrcdir	= @top_srcdir@
+srcdir		= @srcdir@
+VPATH		= @srcdir@
+
+include $(DEPTH)/config/autoconf.mk
+
+# EXTRA_COMPONENTS installs components written JavaScript to
+# dist/bin/components
+EXTRA_COMPONENTS = spatial-navigation.js
+
+ifdef ENABLE_TESTS
+	DIRS += tests
+endif
+
+include $(topsrcdir)/config/rules.mk
diff -r 378495e669f9 toolkit/spatial-navigation/spatial-navigation.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/spatial-navigation/spatial-navigation.js	Tue Jul 01 15:36:38 2008 -0400
@@ -0,0 +1,373 @@
+/* ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is Spatial Navigation.
+ *
+ * The Initial Developer of the Original Code is Mozilla Corporation
+ * Portions created by the Initial Developer are Copyright (C) 2008
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *  Doug Turner <dougt@meer.net>  (Original Author)
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either the GNU General Public License Version 2 or later (the "GPL"), or
+ * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+const Cc = Components.classes;
+const Ci = Components.interfaces;
+
+Components.utils.import("resource://gre/modules/XPCOMUtils.jsm");
+
+//function dump(msg)
+//{
+//    var console = Cc["@mozilla.org/consoleservice;1"].getService(Ci.nsIConsoleService);
+//    console.logStringMessage("*** SNAV: " + msg);
+//}
+
+var gDirectionalBias = 10;
+var gRectFudge = 1;
+
+function SpatialNavigation() {};
+
+SpatialNavigation.prototype = {
+    classDescription: "Spatial Navigation XPCOM Component",
+    classID:          Components.ID("{0E249DC7-0EAF-438E-A553-55F7DFFBB4E1}"),
+    contractID:       "@mozilla.com/spatialnavigation;1",
+    _xpcom_categories: [{ category: "app-startup", service: true }],
+    QueryInterface: XPCOMUtils.generateQI([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
+
+    observe: function(aSubject, aTopic, aData) {
+        var observerService = Cc["@mozilla.org/observer-service;1"].
+	                          getService(Ci.nsIObserverService);
+        switch (aTopic) {
+        case "app-startup":
+            observerService.addObserver(this, "profile-after-change", false);
+            observerService.addObserver(this, "domwindowopened", false);
+            break;
+
+        case "domwindowopened":
+            var window = aSubject;
+            var self = this;
+            window.addEventListener("load", function() {
+                    self._onWindowOpened(self, window);
+                }, false);
+            break;
+
+        case "profile-after-change":
+            // check to see if our preference is enabled.
+            // TBD: add other prefs here.
+            var prefs = Cc["@mozilla.org/preferences-service;1"].getService(Ci.nsIPrefBranch);
+            try {
+                this.mEnabled = prefs.getBoolPref("snav.enabled");
+            } catch(e) {
+                this.mEnabled = false;
+            }
+        }
+    },
+
+    _onWindowOpened: function(self, aWindow) {
+        var wType = aWindow.document.documentElement.getAttribute("windowtype");
+        if (wType != "navigator:browser")
+            return;
+
+        var browser = aWindow.document.getElementById("content");
+        browser.addEventListener("keypress",self._onInputKeyPress, false);
+    },
+
+    _onInputKeyPress: function(event) {
+
+        // TBD: Why not just check this.mEnabled ?
+        var prefs = Cc["@mozilla.org/preferences-service;1"].getService(Ci.nsIPrefBranch);
+        try {
+            this.mEnabled = prefs.getBoolPref("snav.enabled");
+        } catch(e) {
+            this.mEnabled = false;
+        }
+
+        if (!this.mEnabled)
+            return;
+
+        // If it isn't an arrow key, bail.
+        if (event.keyCode != event.DOM_VK_LEFT  &&
+            event.keyCode != event.DOM_VK_RIGHT &&
+            event.keyCode != event.DOM_VK_UP    &&
+            event.keyCode != event.DOM_VK_DOWN  )
+            return;
+
+        function snavfilter(node) {
+
+            if (node instanceof Ci.nsIDOMHTMLLinkElement ||
+                node instanceof Ci.nsIDOMHTMLAnchorElement) {
+                // if a anchor doesn't have a href, don't target it.
+                if (node.href == "")
+                    return Ci.nsIDOMNodeFilter.FILTER_SKIP;
+                return  Ci.nsIDOMNodeFilter.FILTER_ACCEPT;
+            }
+
+            if (node instanceof Ci.nsIDOMHTMLInputElement  ||
+                node instanceof Ci.nsIDOMHTMLSelectElement ||
+                node instanceof Ci.nsIDOMHTMLOptionElement)
+                return Ci.nsIDOMNodeFilter.FILTER_ACCEPT;
+            return Ci.nsIDOMNodeFilter.FILTER_SKIP;
+        }
+        var bestElementToFocus = null;
+        var distanceToBestElement = Infinity;
+        var focusedRect = inflateRect(event.target.getBoundingClientRect(),
+                                      - gRectFudge);
+        var doc = event.target.ownerDocument;
+
+        var treeWalker = doc.createTreeWalker(doc, Ci.nsIDOMNodeFilter.SHOW_ELEMENT, snavfilter, false);
+        var nextNode;
+
+        while ((nextNode = treeWalker.nextNode())) {
+
+            if (nextNode == event.target)
+                continue;
+
+            var nextRect = inflateRect(nextNode.getBoundingClientRect(),
+                                       - gRectFudge);
+
+            if (! isRectInDirection(event, focusedRect, nextRect))
+                continue;
+
+            var distance = spatialDistance(event, focusedRect, nextRect);
+
+            if (distance <= distanceToBestElement && distance > 0) {
+                distanceToBestElement = distance;
+                bestElementToFocus = nextNode;
+            }
+        }
+
+        if (bestElementToFocus != null) {
+            //dump("focusing element  " + bestElementToFocus.nodeName);
+            bestElementToFocus.focus();
+        } else {
+            // couldn't find anything.  just advance and hope.
+            //dump("advancing focus");
+            var windowMediator = Cc['@mozilla.org/appshell/window-mediator;1'].
+            getService(Ci.nsIWindowMediator);
+            var window = windowMediator.getMostRecentWindow("navigator:browser");
+            window.document.commandDispatcher.advanceFocus();
+        }
+
+        event.preventDefault();
+        event.stopPropagation();
+    },
+};
+
+function isRectInDirection(event, focusedRect, anotherRect)
+{
+    if (event.keyCode == event.DOM_VK_LEFT) {
+        return (anotherRect.left < focusedRect.left);
+    }
+
+    if (event.keyCode == event.DOM_VK_RIGHT) {
+        return (anotherRect.right > focusedRect.right);
+    }
+
+    if (event.keyCode == event.DOM_VK_UP) {
+        return (anotherRect.top < focusedRect.top);
+    }
+
+    if (event.keyCode == event.DOM_VK_DOWN) {
+        return (anotherRect.bottom > focusedRect.bottom);
+    }
+    return false;
+}
+
+
+function inflateRect(rect, value)
+{
+    var newRect = new Object();
+
+    newRect.left   = rect.left - value;
+    newRect.top    = rect.top - value;
+    newRect.right  = rect.right  + value;
+    newRect.bottom = rect.bottom + value;
+    return newRect;
+}
+
+function Contains(a, b)
+{
+    return ( (b.left  <= a.right) &&
+             (b.right >= a.left)  &&
+             (b.top  <= a.bottom) &&
+             (b.bottom >= a.top) );
+}
+
+function spatialDistance(event, a, b)
+{
+    var inlineNavigation = false;
+    var mx, my, nx, ny;
+
+    if (event.keyCode == event.DOM_VK_LEFT) {
+
+        //  |---|
+        //  |---|
+        //
+        //  |---|  |---|
+        //  |---|  |---|
+        //
+        //  |---|
+        //  |---|
+        //
+
+        if (a.top > b.bottom) {
+            // the b rect is above a.
+            mx = a.left;
+            my = a.top;
+            nx = b.right;
+            ny = b.bottom;
+        }
+        else if (a.bottom < b.top) {
+            // the b rect is below a.
+            mx = a.left;
+            my = a.bottom;
+            nx = b.right;
+            ny = b.top;
+        }
+        else {
+            mx = a.left;
+            my = 0;
+            nx = b.right;
+            ny = 0;
+        }
+    } else if (event.keyCode == event.DOM_VK_RIGHT) {
+
+        //         |---|
+        //         |---|
+        //
+        //  |---|  |---|
+        //  |---|  |---|
+        //
+        //         |---|
+        //         |---|
+        //
+
+        if (a.top > b.bottom) {
+            // the b rect is above a.
+            mx = a.right;
+            my = a.top;
+            nx = b.left;
+            ny = b.bottom;
+        }
+        else if (a.bottom < b.top) {
+            // the b rect is below a.
+            mx = a.right;
+            my = a.bottom;
+            nx = b.left;
+            ny = b.top;
+        } else {
+            mx = a.right;
+            my = 0;
+            nx = b.left;
+            ny = 0;
+        }
+    } else if (event.keyCode == event.DOM_VK_UP) {
+
+        //  |---|  |---|  |---|
+        //  |---|  |---|  |---|
+        //
+        //         |---|
+        //         |---|
+        //
+
+        if (a.left > b.right) {
+            // the b rect is to the left of a.
+            mx = a.left;
+            my = a.top;
+            nx = b.right;
+            ny = b.bottom;
+        } else if (a.right < b.left) {
+            // the b rect is to the right of a
+            mx = a.right;
+            my = a.top;
+            nx = b.left;
+            ny = b.bottom;
+        } else {
+            // both b and a share some common x's.
+            mx = 0;
+            my = a.top;
+            nx = 0;
+            ny = b.bottom;
+        }
+    } else if (event.keyCode == event.DOM_VK_DOWN) {
+
+        //         |---|
+        //         |---|
+        //
+        //  |---|  |---|  |---|
+        //  |---|  |---|  |---|
+        //
+
+        if (a.left > b.right) {
+            // the b rect is to the left of a.
+            mx = a.left;
+            my = a.bottom;
+            nx = b.right;
+            ny = b.top;
+        } else if (a.right < b.left) {
+            // the b rect is to the right of a
+            mx = a.right;
+            my = a.bottom;
+            nx = b.left;
+            ny = b.top;
+        } else {
+            // both b and a share some common x's.
+            mx = 0;
+            my = a.bottom;
+            nx = 0;
+            ny = b.top;
+        }
+    }
+
+    var scopedRect = inflateRect(a, gRectFudge);
+
+    if (event.keyCode == event.DOM_VK_LEFT ||
+        event.keyCode == event.DOM_VK_RIGHT) {
+        scopedRect.left = 0;
+        scopedRect.right = Infinity;
+        inlineNavigation = Contains(scopedRect, b);
+    }
+    else if (event.keyCode == event.DOM_VK_UP ||
+             event.keyCode == event.DOM_VK_DOWN) {
+        scopedRect.top = 0;
+        scopedRect.bottom = Infinity;
+        inlineNavigation = Contains(scopedRect, b);
+    }
+
+    var d = Math.pow((mx-nx), 2) + Math.pow((my-ny), 2);
+
+    // prefer elements directly aligned with the focused element
+    if (inlineNavigation)
+        d /= gDirectionalBias;
+
+    return d;
+}
+
+var components = [SpatialNavigation];
+
+function NSGetModule(compMgr, fileSpec) {
+    return XPCOMUtils.generateModule(components);
+}
diff -r 378495e669f9 toolkit/spatial-navigation/tests/Makefile.in
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/spatial-navigation/tests/Makefile.in	Tue Jul 01 15:36:38 2008 -0400
@@ -0,0 +1,55 @@
+# ***** BEGIN LICENSE BLOCK *****
+# Version: MPL 1.1/GPL 2.0/LGPL 2.1
+#
+# The contents of this file are subject to the Mozilla Public License Version
+# 1.1 (the "License"); you may not use this file except in compliance with
+# the License. You may obtain a copy of the License at
+# http://www.mozilla.org/MPL/
+#
+# Software distributed under the License is distributed on an "AS IS" basis,
+# WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+# for the specific language governing rights and limitations under the
+# License.
+#
+# The Original Code is mozilla.org build system.
+#
+# The Initial Developer of the Original Code is Mozilla Corporation
+# Portions created by the Initial Developer are Copyright (C) 2008
+# the Initial Developer. All Rights Reserved.
+#
+# Contributor(s):
+#  Doug Turner <dougt@meer.net>
+#
+# Alternatively, the contents of this file may be used under the terms of
+# either the GNU General Public License Version 2 or later (the "GPL"), or
+# the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+# in which case the provisions of the GPL or the LGPL are applicable instead
+# of those above. If you wish to allow use of your version of this file only
+# under the terms of either the GPL or the LGPL, and not to allow others to
+# use your version of this file under the terms of the MPL, indicate your
+# decision by deleting the provisions above and replace them with the notice
+# and other provisions required by the GPL or the LGPL. If you do not delete
+# the provisions above, a recipient may use your version of this file under
+# the terms of any one of the MPL, the GPL or the LGPL.
+#
+# ***** END LICENSE BLOCK *****
+
+DEPTH		= ../../..
+topsrcdir	= @top_srcdir@
+srcdir		= @srcdir@
+VPATH		= @srcdir@
+relativesrcdir	= toolkit/spatial-navigation/tests
+
+include $(DEPTH)/config/autoconf.mk
+
+MODULE		= test_snav
+
+MOCHI_TESTS = mochitest/test_snav.html \
+              $(NULL)
+
+MOCHI_CONTENT = $(NULL)
+
+include $(topsrcdir)/config/rules.mk
+
+libs:: $(MOCHI_TESTS) $(MOCHI_CONTENT)
+	$(INSTALL) $(foreach f,$^,"$f") $(DEPTH)/_tests/testing/mochitest/tests/$(relativesrcdir)
diff -r 378495e669f9 toolkit/spatial-navigation/tests/mochitest/test_snav.html
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/spatial-navigation/tests/mochitest/test_snav.html	Tue Jul 01 15:36:38 2008 -0400
@@ -0,0 +1,72 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=436084
+-->
+<head>
+  <title>Test for Bug 436084</title>
+  <script type="text/javascript" src="/MochiKit/MochiKit.js"></script>
+  <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <script type="text/javascript" src="/tests/SimpleTest/EventUtils.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+</head>
+<body>
+<a target="_blank" id="start" href="https://bugzilla.mozilla.org/show_bug.cgi?id=436084">Mozilla Bug 436084</a>
+<p id="display"></p>
+<div id="content">
+<table
+ style="text-align: left; width: 100%; margin-left: auto; margin-right: auto;" border="1" cellpadding="2" cellspacing="2">
+  <tbody>
+    <tr>
+      <td style="vertical-align: top; text-align: center;"><a id="1" href="a">test</a></td>
+      <td style="vertical-align: top; text-align: center;"><a id="2" href="a">test</a></td>
+      <td style="vertical-align: top; text-align: center;"><a id="3" href="a">test</a></td>
+    </tr>
+    <tr>
+      <td style="vertical-align: top; text-align: center;"><a id="4" href="a">test</a></td>
+      <td style="vertical-align: top; text-align: center;"><a id="5" href="a">test</a></td>
+      <td style="vertical-align: top; text-align: center;"><a id="6" href="a">test</a></td>
+    </tr>
+    <tr>
+      <td style="vertical-align: top; text-align: center;"><a id="7" href="a">test</a></td>
+      <td style="vertical-align: top; text-align: center;"><a id="8" href="a">test</a></td>
+      <td style="vertical-align: top; text-align: center;"><a id="9" href="a">test</a></td>
+    </tr>
+  </tbody>
+</table>
+
+  
+</div>
+<pre id="test">
+<script class="testbody" type="text/javascript">
+
+/** Test for Bug 436084 **/
+
+function moveAndVerify(direction, value)
+{
+ sendKey(direction, document.activeElement);
+ ok(document.activeElement.getAttribute("id") == value, "Move");
+}
+
+// get to a known place.
+document.getElementById("start").focus();
+
+// from start.
+moveAndVerify("DOWN", "1");
+
+for (var i = 1 ; i < 10 ; i ++) {
+moveAndVerify("DOWN", "4");
+moveAndVerify("DOWN", "7");
+moveAndVerify("RIGHT", "8");
+moveAndVerify("RIGHT", "9");
+moveAndVerify("UP", "6");
+moveAndVerify("UP", "3");
+moveAndVerify("LEFT", "2");
+moveAndVerify("LEFT", "1");
+}
+
+</script>
+</pre>
+</body>
+</html>
+