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 jquery#2279, jquery#4452, and jquery#4835.

Author: jeresig

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);
 

src/support.js

@@ -56,10 +56,7 @@
 		// (WebKit defaults to false instead of true, IE too, if it's in an optgroup)
 		optSelected: document.createElement("select").appendChild( document.createElement("option") ).selected,
 
-		parentNode: div.removeChild( div.appendChild( document.createElement("div") ) ).parentNode === null,
-
 		// Will be defined later
-		deleteExpando: true,
 		checkClone: false,
 		scriptEval: false,
 		noCloneEvent: true,
@@ -69,7 +66,7 @@
 	script.type = "text/javascript";
 	try {
 		script.appendChild( document.createTextNode( "window." + id + "=1;" ) );
-	} catch( scriptError ) {}
+	} catch(e) {}
 
 	root.insertBefore( script, root.firstChild );
 
@@ -81,15 +78,6 @@
 		delete window[ id ];
 	}
 
-	// Test to see if it's possible to delete an expando from an element
-	// Fails in Internet Explorer
-	try {
-		delete script.test;
-	
-	} catch( expandoError ) {
-		jQuery.support.deleteExpando = false;
-	}
-
 	root.removeChild( script );
 
 	if ( div.attachEvent && div.fireEvent ) {
@@ -120,7 +108,6 @@
 		document.body.appendChild( div );
 		jQuery.boxModel = jQuery.support.boxModel = div.offsetWidth === 2;
 		document.body.removeChild( div ).style.display = 'none';
-
 		div = null;
 	});
 

test/unit/core.js

@@ -201,14 +201,20 @@ test("noConflict", function() {
 });
 
 test("trim", function() {
-  expect(4);
+	expect(9);
 
-  var nbsp = String.fromCharCode(160);
+	var nbsp = String.fromCharCode(160);
 
-  equals( jQuery.trim("hello  "), "hello", "trailing space" );
-  equals( jQuery.trim("  hello"), "hello", "leading space" );
-  equals( jQuery.trim("  hello   "), "hello", "space on both sides" );
-  equals( jQuery.trim("  " + nbsp + "hello  " + nbsp + " "), "hello", " " );
+	equals( jQuery.trim("hello  "), "hello", "trailing space" );
+	equals( jQuery.trim("  hello"), "hello", "leading space" );
+	equals( jQuery.trim("  hello   "), "hello", "space on both sides" );
+	equals( jQuery.trim("  " + nbsp + "hello  " + nbsp + " "), "hello", " " );
+
+	equals( jQuery.trim(), "", "Nothing in." );
+	equals( jQuery.trim( undefined ), "", "Undefined" );
+	equals( jQuery.trim( null ), "", "Null" );
+	equals( jQuery.trim( 5 ), "5", "Number" );
+	equals( jQuery.trim( false ), "false", "Boolean" );
 });
 
 test("isPlainObject", function() {