diff --git a/dom/ranges/Range-collapse.html b/dom/ranges/Range-collapse.html
index b30731ea2292c7..3ca95ac0123595 100644
--- a/dom/ranges/Range-collapse.html
+++ b/dom/ranges/Range-collapse.html
@@ -12,14 +12,9 @@
 	var range;
 	if (rangeEndpoints == "detached") {
 		range = document.createRange();
-		range.detach();
-		assert_throws("INVALID_STATE_ERR", function() {
-			range.collapse(toStart);
-		}, "Detached Range must throw INVALID_STATE_ERR on .collapse()");
-		assert_throws("INVALID_STATE_ERR", function() {
-			range.collapsed;
-		}, "Detached Range must throw INVALID_STATE_ERR on .collapsed access");
-		return;
+		range.detach(); // should be a no-op and therefore the following should not throw
+		range.collapse(toStart);
+		assert_equals(true, range.collapsed);
 	}
 
 	// Have to account for Ranges involving Documents!
@@ -37,7 +32,10 @@
 		&& range.startOffset == range.endOffset,
 		"collapsed must be true if and only if the start and end are equal");
 
-	range.collapse(toStart);
+	if(undefined == toStart)
+        	range.collapse()
+	else
+		range.collapse(toStart);
 
 	assert_equals(range.startContainer, expectedContainer,
 		"Wrong startContainer");
@@ -128,6 +126,11 @@
 		eval(ranges[i]),
 		false
 	]);
+	tests.push([
+		"Range " + i + " " + ranges[i] + ", toStart omitted",
+		eval(ranges[i]),
+		undefined
+	]);
 }
 generate_tests(testCollapse, tests);