Landing a faster trim method. Based upon the work by Travis Hardiman and DBJDBJ. More details here: http://forum.jquery.com/topic/faster-jquery-trim Fixes #2279, #4452, and #4835.

src/core.js

@@ -27,7 +27,8 @@ var jQuery = function( selector, context ) {
 	rnotwhite = /\S/,
 
 	// Used for trimming whitespace
-	rtrim = /^(\s|\u00A0)+|(\s|\u00A0)+$/g,
+	trimLeft = /^\s+/,
+	trimRight = /\s+$/,
 
 	// Match a standalone tag
 	rsingleTag = /^<(\w+)\s*\/?>(?:<\/\1>)?$/,
@@ -567,9 +568,20 @@ jQuery.extend({
 		return object;
 	},
 
-	trim: function( text ) {
-		return (text || "").replace( rtrim, "" );
-	},
+	// Use native String.trim function wherever possible
+	trim: String.trim ?
+		function( text ) {
+			return text == null ?
+				"" :
+				String.trim( text );
+		} :
+
+		// Otherwise use our own trimming functionality
+		function( text ) {
+			return text == null ?
+				"" :
+				text.toString().replace( trimLeft, "" ).replace( trimRight, "" );
+		},
 
 	// results is for internal usage only
 	makeArray: function( array, results ) {
@@ -720,6 +732,13 @@ if ( indexOf ) {
 	};
 }
 
+// Verify that \s matches non-breaking spaces
+// (IE fails on this test)
+if ( !/\s/.test( "\xA0" ) ) {
+	trimLeft = /^[\s\xA0]+/;
+	trimRight = /[\s\xA0]+$/;
+}
+
 // All jQuery objects should point back to these
 rootjQuery = jQuery(document);