--- a/editing.html	Tue Oct 11 13:20:52 2011 -0600
+++ b/editing.html	Tue Oct 11 15:30:30 2011 -0600
@@ -925,21 +925,22 @@
   <var title="">offset</var>).
 </ol>
 
+<p class=comments>For collapseToStart/End, IE9 mutates the existing range,
+while Firefox 9.0a2 and Chrome 15 dev replace it with a new one.  The spec
+follows the majority and replaces it with a new one, leaving the old Range
+object unchanged.
+
 <p>The <dfn id=dom-selection-collapsetostart title=dom-Selection-collapseToStart><code>collapseToStart()</code></dfn> method
 must <a class=external data-anolis-spec=dom href=http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#concept-throw title=concept-throw>throw</a> an <code class=external data-anolis-spec=dom><a href=http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#invalidstateerror>InvalidStateError</a></code> exception if the <a class=external data-anolis-spec=dom href=http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#context-object>context object</a>'s
-<a class=external data-anolis-spec=dom href=http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#concept-range title=concept-range>range</a> is null. Otherwise, it must invoke the <code title=dom-Selection-collapse><a href=#dom-selection-collapse>collapse()</a></code> method with
-the <a class=external data-anolis-spec=dom href=http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#concept-range-start-node title=concept-range-start-node>start node</a> and <a class=external data-anolis-spec=dom href=http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#concept-range-start-offset title=concept-range-start-offset>start offset</a> of the <a class=external data-anolis-spec=dom href=http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#context-object>context object</a>'s <a class=external data-anolis-spec=dom href=http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#concept-range title=concept-range>range</a> as
-the arguments.
+<a class=external data-anolis-spec=dom href=http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#concept-range title=concept-range>range</a> is null.  Otherwise, it must set the <a class=external data-anolis-spec=dom href=http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#context-object>context object</a>'s <a class=external data-anolis-spec=dom href=http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#concept-range title=concept-range>range</a> to
+a new <a class=external data-anolis-spec=dom href=http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#concept-range title=concept-range>range</a> object with <a class=external data-anolis-spec=dom href=http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#concept-range-start title=concept-range-start>start</a> and <a class=external data-anolis-spec=dom href=http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#concept-range-end title=concept-range-end>end</a> both equal to the
+<a class=external data-anolis-spec=dom href=http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#context-object>context object</a>'s old <a class=external data-anolis-spec=dom href=http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#concept-range title=concept-range>range</a>'s <a class=external data-anolis-spec=dom href=http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#concept-range-start title=concept-range-start>start</a>.
 
 <p>The <dfn id=dom-selection-collapsetoend title=dom-Selection-collapseToEnd><code>collapseToEnd()</code></dfn> method
 must <a class=external data-anolis-spec=dom href=http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#concept-throw title=concept-throw>throw</a> an <code class=external data-anolis-spec=dom><a href=http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#invalidstateerror>InvalidStateError</a></code> exception if the <a class=external data-anolis-spec=dom href=http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#context-object>context object</a>'s
-<a class=external data-anolis-spec=dom href=http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#concept-range title=concept-range>range</a> is null. Otherwise, it must invoke the <code title=dom-Selection-collapse><a href=#dom-selection-collapse>collapse()</a></code> method with
-the <a class=external data-anolis-spec=dom href=http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#concept-range-end-node title=concept-range-end-node>end node</a> and <a class=external data-anolis-spec=dom href=http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#concept-range-end-offset title=concept-range-end-offset>end offset</a> values of the last <a class=external data-anolis-spec=dom href=http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#concept-range title=concept-range>range</a> object in the
-list as the arguments.
-
-<p class=XXX>This implies that they'll replace the range object instead of
-changing it.  Will they?  Needs testing.  It seems like they shouldn't.  Same
-for collapse() itself.
+<a class=external data-anolis-spec=dom href=http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#concept-range title=concept-range>range</a> is null.  Otherwise, it must set the <a class=external data-anolis-spec=dom href=http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#context-object>context object</a>'s <a class=external data-anolis-spec=dom href=http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#concept-range title=concept-range>range</a> to
+a new <a class=external data-anolis-spec=dom href=http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#concept-range title=concept-range>range</a> object with <a class=external data-anolis-spec=dom href=http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#concept-range-start title=concept-range-start>start</a> and <a class=external data-anolis-spec=dom href=http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#concept-range-end title=concept-range-end>end</a> both equal to the
+<a class=external data-anolis-spec=dom href=http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#context-object>context object</a>'s old <a class=external data-anolis-spec=dom href=http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#concept-range title=concept-range>range</a>'s <a class=external data-anolis-spec=dom href=http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#concept-range-end title=concept-range-end>end</a>.
 
 <p class=comments>Reverse-engineered circa January 2011.  IE doesn't support it, so I'm
 relying on Firefox (implemented extend() sometime before 2000) and WebKit
--- a/selecttest/Selection-collapseToEnd.html	Tue Oct 11 13:20:52 2011 -0600
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,11 +0,0 @@
-<!DOCTYPE html>
-<title>The collapseToEnd method</title>
-<div id=log></div>
-<script src=http://w3c-test.org/resources/testharness.js></script>
-<script>
-test(function() {
-  var sel = getSelection();
-  sel.removeAllRanges();
-  assert_throws("INVALID_STATE_ERR", function() { sel.collapseToEnd(); })
-});
-</script>
--- a/selecttest/Selection-collapseToStart.html	Tue Oct 11 13:20:52 2011 -0600
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,11 +0,0 @@
-<!DOCTYPE html>
-<title>The collapseToStart method</title>
-<div id=log></div>
-<script src=http://w3c-test.org/resources/testharness.js></script>
-<script>
-test(function() {
-  var sel = getSelection();
-  sel.removeAllRanges();
-  assert_throws("INVALID_STATE_ERR", function() { sel.collapseToStart(); })
-});
-</script>
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/selecttest/Selection-collapseToStartEnd.html	Tue Oct 11 15:30:30 2011 -0600
@@ -0,0 +1,123 @@
+<!doctype html>
+<title>Selection.collapseTo(Start|End)() tests</title>
+<div id=log></div>
+<script src=http://w3c-test.org/resources/testharness.js></script>
+<script src=common.js></script>
+<script>
+"use strict";
+
+function testCollapseToStartEnd(range) {
+}
+
+// Also test a selection with no ranges
+testRanges.unshift("[]");
+
+for (var i = 0; i < testRanges.length; i++) {
+	test(function() {
+		selection.removeAllRanges();
+		var endpoints = eval(testRanges[i]);
+		if (!endpoints.length) {
+			assert_throws("INVALID_STATE_ERR", function() {
+				selection.collapseToStart();
+			}, "Must throw InvalidStateErr if the selection's range is null");
+			return;
+		}
+
+		var addedRange = ownerDocument(endpoints[0]).createRange();
+		addedRange.setStart(endpoints[0], endpoints[1]);
+		addedRange.setEnd(endpoints[2], endpoints[3]);
+		selection.addRange(addedRange);
+
+		// We don't penalize browsers here for mishandling addRange() and
+		// adding a different range than we specified.  They fail addRange()
+		// tests for that, and don't have to fail collapseToStart/End() tests
+		// too.  They do fail if they throw unexpectedly, though.  I also fail
+		// them if there's no range at all, because otherwise they could pass
+		// all tests if addRange() always does nothing and collapseToStart()
+		// always throws.
+		assert_equals(selection.rangeCount, 1,
+			"Sanity check: rangeCount must equal 1 after addRange()");
+
+		var expectedEndpoint = [
+			selection.getRangeAt(0).startContainer,
+			selection.getRangeAt(0).startOffset
+		];
+
+		selection.collapseToStart();
+
+		assert_equals(selection.rangeCount, 1,
+			"selection.rangeCount must equal 1");
+		assert_equals(selection.focusNode, expectedEndpoint[0],
+			"focusNode must equal the original start node");
+		assert_equals(selection.focusOffset, expectedEndpoint[1],
+			"focusOffset must equal the original start offset");
+		assert_equals(selection.anchorNode, expectedEndpoint[0],
+			"anchorNode must equal the original start node");
+		assert_equals(selection.anchorOffset, expectedEndpoint[1],
+			"anchorOffset must equal the original start offset");
+		assert_equals(addedRange.startContainer, endpoints[0],
+			"collapseToStart() must not change the startContainer of the selection's original range");
+		assert_equals(addedRange.startOffset, endpoints[1],
+			"collapseToStart() must not change the startOffset of the selection's original range");
+		assert_equals(addedRange.endContainer, endpoints[2],
+			"collapseToStart() must not change the endContainer of the selection's original range");
+		assert_equals(addedRange.endOffset, endpoints[3],
+			"collapseToStart() must not change the endOffset of the selection's original range");
+	}, "Range " + i + " " + testRanges[i] + " collapseToStart()");
+
+	// Copy-paste of above
+	test(function() {
+		selection.removeAllRanges();
+		var endpoints = eval(testRanges[i]);
+		if (!endpoints.length) {
+			assert_throws("INVALID_STATE_ERR", function() {
+				selection.collapseToEnd();
+			}, "Must throw InvalidStateErr if the selection's range is null");
+			return;
+		}
+
+		var addedRange = ownerDocument(endpoints[0]).createRange();
+		addedRange.setStart(endpoints[0], endpoints[1]);
+		addedRange.setEnd(endpoints[2], endpoints[3]);
+		selection.addRange(addedRange);
+
+		// We don't penalize browsers here for mishandling addRange() and
+		// adding a different range than we specified.  They fail addRange()
+		// tests for that, and don't have to fail collapseToStart/End() tests
+		// too.  They do fail if they throw unexpectedly, though.  I also fail
+		// them if there's no range at all, because otherwise they could pass
+		// all tests if addRange() always does nothing and collapseToStart()
+		// always throws.
+		assert_equals(selection.rangeCount, 1,
+			"Sanity check: rangeCount must equal 1 after addRange()");
+
+		var expectedEndpoint = [
+			selection.getRangeAt(0).endContainer,
+			selection.getRangeAt(0).endOffset
+		];
+
+		selection.collapseToEnd();
+
+		assert_equals(selection.rangeCount, 1,
+			"selection.rangeCount must equal 1");
+		assert_equals(selection.focusNode, expectedEndpoint[0],
+			"focusNode must equal the original end node");
+		assert_equals(selection.focusOffset, expectedEndpoint[1],
+			"focusOffset must equal the original end offset");
+		assert_equals(selection.anchorNode, expectedEndpoint[0],
+			"anchorNode must equal the original end node");
+		assert_equals(selection.anchorOffset, expectedEndpoint[1],
+			"anchorOffset must equal the original end offset");
+		assert_equals(addedRange.startContainer, endpoints[0],
+			"collapseToEnd() must not change the startContainer of the selection's original range");
+		assert_equals(addedRange.startOffset, endpoints[1],
+			"collapseToEnd() must not change the startOffset of the selection's original range");
+		assert_equals(addedRange.endContainer, endpoints[2],
+			"collapseToEnd() must not change the endContainer of the selection's original range");
+		assert_equals(addedRange.endOffset, endpoints[3],
+			"collapseToEnd() must not change the endOffset of the selection's original range");
+	}, "Range " + i + " " + testRanges[i] + " collapseToEnd()");
+}
+
+testDiv.style.display = "none";
+</script>
--- a/source.html	Tue Oct 11 13:20:52 2011 -0600
+++ b/source.html	Tue Oct 11 15:30:30 2011 -0600
@@ -868,23 +868,24 @@
   <var>offset</var>).
 </ol>
 
+<p class=comments>For collapseToStart/End, IE9 mutates the existing range,
+while Firefox 9.0a2 and Chrome 15 dev replace it with a new one.  The spec
+follows the majority and replaces it with a new one, leaving the old Range
+object unchanged.
+
 <p>The <dfn
 title=dom-Selection-collapseToStart><code>collapseToStart()</code></dfn> method
 must [[throw]] an [[InvalidStateError]] exception if the [[contextobject]]'s
-[[range]] is null. Otherwise, it must invoke the [[selcollapse|]] method with
-the [[startnode]] and [[startoffset]] of the [[contextobject]]'s [[range]] as
-the arguments.
+[[range]] is null.  Otherwise, it must set the [[contextobject]]'s [[range]] to
+a new [[range]] object with [[rangestart]] and [[rangeend]] both equal to the
+[[contextobject]]'s old [[range]]'s [[rangestart]].
 
 <p>The <dfn
 title=dom-Selection-collapseToEnd><code>collapseToEnd()</code></dfn> method
 must [[throw]] an [[InvalidStateError]] exception if the [[contextobject]]'s
-[[range]] is null. Otherwise, it must invoke the [[selcollapse|]] method with
-the [[endnode]] and [[endoffset]] values of the last [[range]] object in the
-list as the arguments.
-
-<p class=XXX>This implies that they'll replace the range object instead of
-changing it.  Will they?  Needs testing.  It seems like they shouldn't.  Same
-for collapse() itself.
+[[range]] is null.  Otherwise, it must set the [[contextobject]]'s [[range]] to
+a new [[range]] object with [[rangestart]] and [[rangeend]] both equal to the
+[[contextobject]]'s old [[range]]'s [[rangeend]].
 
 <p class=comments>Reverse-engineered circa January 2011.  IE doesn't support it, so I'm
 relying on Firefox (implemented extend() sometime before 2000) and WebKit