Brought back the compareDocumentPosition code. While it is redundant in Firefox it's much faster than using indexOf.

1 files changed, 10 insertions, 2 deletions

diff --git a/src/selector.js b/src/selector.js
index c97ba61ff..6538d9706 100644
--- a/src/selector.js
+++ b/src/selector.js
@@ -684,7 +684,15 @@ try {
 
 var sortOrder;
 
-if ( Array.prototype.indexOf ) {
+if ( document.documentElement.compareDocumentPosition ) {
+	sortOrder = function( a, b ) {
+		var ret = a.compareDocumentPosition(b) & 4 ? -1 : a === b ? 0 : 1;
+		if ( ret === 0 ) {
+			hasDuplicate = true;
+		}
+		return ret;
+	};
+} else if ( Array.prototype.indexOf ) {
 	var indexOf = Array.prototype.indexOf,
 		allSort = document.getElementsByTagName("*");
 
@@ -695,7 +703,7 @@ if ( Array.prototype.indexOf ) {
 		}
 		return ret;
 	};
-} else if ( document.documentElement.sourceIndex === 1 ) {
+} else if ( "sourceIndex" in document.documentElement ) {
 	sortOrder = function( a, b ) {
 		var ret = a.sourceIndex - b.sourceIndex;
 		if ( ret === 0 ) {