diff --git a/src/jquery/jquery.js b/src/jquery/jquery.js
index a8872dfb8e..910c11b21a 100644
--- a/src/jquery/jquery.js
+++ b/src/jquery/jquery.js
@@ -1345,10 +1345,7 @@ jQuery.extend({
 
 		// internal only, use is(".class")
 		has: function( t, c ) {
-			t = t.className || t;
-			// escape regex characters
-			c = c.replace(/([\.\\\+\*\?\[\^\]\$\(\)\{\}\=\!\<\>\|\:])/g, "\\$1");
-			return t && new RegExp("(^|\\s)" + c + "(\\s|$)").test( t );
+			return jQuery.inArray( c, (t.className || t).toString().split(/\s+/) ) > -1;
 		}
 	},
 
diff --git a/src/selector/selector.js b/src/selector/selector.js
index 9d36ca7077..1c6d80c1ee 100644
--- a/src/selector/selector.js
+++ b/src/selector/selector.js
@@ -76,7 +76,7 @@ jQuery.extend({
 		/^(:)([\w-]+)\("?'?(.*?(\(.*?\))?[^(]*?)"?'?\)/i,
 
 		// Match: :even, :last-chlid, #id, .class
-		/^([:.#]*)([\w\u0128-\uFFFF*-]+)/i
+		/^([:.#]*)((?:[\w\u0128-\uFFFF*-]|\\.)+)/i
 	],
 
 	token: [
@@ -205,7 +205,7 @@ jQuery.extend({
 
 				} else {
 					// Optomize for the case nodeName#idName
-					var re2 = /^(\w+)(#)([\w\u0128-\uFFFF*-]+)/i;
+					var re2 = /^(\w+)(#)((?:[\w\u0128-\uFFFF*-]|\\.)+)/i;
 					var m = re2.exec(t);
 					
 					// Re-organize the results, so that they're consistent
@@ -215,10 +215,12 @@ jQuery.extend({
 					} else {
 						// Otherwise, do a traditional filter check for
 						// ID, class, and element selectors
-						re2 = /^([#.]?)([\w\u0128-\uFFFF*-]*)/i;
+						re2 = /^([#.]?)((?:[\w\u0128-\uFFFF*-]|\\.)*)/i;
 						m = re2.exec(t);
 					}
 
+					m[2] = m[2].replace(/\\/g, "");
+
 					var elem = ret[ret.length-1];
 
 					// Try to do a global search by ID, where we can
@@ -236,10 +238,6 @@ jQuery.extend({
 						ret = r = oid && (!m[3] || jQuery.nodeName(oid, m[3])) ? [oid] : [];
 
 					} else {
-						// Pre-compile a regular expression to handle class searches
-						if ( m[1] == "." )
-							var rec = new RegExp("(^|\\s)" + m[2] + "(\\s|$)");
-
 						// We need to find all descendant elements, it is more
 						// efficient to use getAll() when we are already further down
 						// the tree - we try to recognize that here
@@ -257,7 +255,7 @@ jQuery.extend({
 						// It's faster to filter by class and be done with it
 						if ( m[1] == "." )
 							r = jQuery.grep( r, function(e) {
-								return rec.test(e.className);
+								return jQuery.className.has(e, m[2]);
 							});
 
 						// Same with ID filtering
@@ -330,6 +328,8 @@ jQuery.extend({
 					if ( jQuery.expr[ m[1] ]._resort )
 						m = jQuery.expr[ m[1] ]._resort( m );
 
+					m[2] = m[2].replace(/\\/g, "");
+
 					return false;
 				}
 			});
@@ -342,17 +342,8 @@ jQuery.extend({
 			if ( m[1] == ":" && m[2] == "not" )
 				r = jQuery.filter(m[3], r, true).r;
 
-			// Handle classes as a special case (this will help to
-			// improve the speed, as the regexp will only be compiled once)
-			else if ( m[1] == "." ) {
-
-				var re = new RegExp("(^|\\s)" + m[2] + "(\\s|$)");
-				r = jQuery.grep( r, function(e){
-					return re.test(e.className || "");
-				}, not);
-
 			// Otherwise, find the expression to execute
-			} else {
+			else {
 				var f = jQuery.expr[m[1]];
 				if ( typeof f != "string" )
 					f = jQuery.expr[m[1]][m[2]];
diff --git a/src/selector/selectorTest.js b/src/selector/selectorTest.js
index 5cd3b23e0e..9180743277 100644
--- a/src/selector/selectorTest.js
+++ b/src/selector/selectorTest.js
@@ -22,7 +22,7 @@ test("broken", function() {
 });
 
 test("id", function() {
-	expect(17);
+	expect(23);
 	t( "ID Selector", "#body", ["body"] );
 	t( "ID Selector w/ Element", "body#body", ["body"] );
 	t( "ID Selector w/ Element", "ul#first", [] );
@@ -33,6 +33,13 @@ test("id", function() {
 	t( "Descendant ID selector using UTF8", "div #台北", ["台北"] );
 	t( "Child ID selector using UTF8", "form > #台北", ["台北"] );
 	
+	t( "Escaped ID", "#foo\\:bar", ["foo:bar"] );
+	t( "Escaped ID", "#test\\.foo\\[5\\]bar", ["test.foo[5]bar"] );
+	t( "Descendant escaped ID", "div #foo\\:bar", ["foo:bar"] );
+	t( "Descendant escaped ID", "div #test\\.foo\\[5\\]bar", ["test.foo[5]bar"] );
+	t( "Child escaped ID", "form > #foo\\:bar", ["foo:bar"] );
+	t( "Child escaped ID", "form > #test\\.foo\\[5\\]bar", ["test.foo[5]bar"] );
+	
 	t( "ID Selector, child ID present", "#form > #radio1", ["radio1"] );  // bug #267
 	t( "ID Selector, not an ancestor ID", "#form  #first", [] );
 	t( "ID Selector, not a child ID", "#form > #option1a", [] );
@@ -48,7 +55,7 @@ test("id", function() {
 });
 
 test("class", function() {
-	expect(10);
+	expect(16);
 	t( "Class Selector", ".blog", ["mark","simon"] );
 	t( "Class Selector", ".blog.link", ["simon"] );
 	t( "Class Selector w/ Element", "a.blog", ["mark","simon"] );
@@ -60,6 +67,13 @@ test("class", function() {
 	t( "Class selector using UTF8", ".台北Táiběi, .台北", ["utf8class1","utf8class2"] );
 	t( "Descendant class selector using UTF8", "div .台北Táiběi", ["utf8class1"] );
 	t( "Child class selector using UTF8", "form > .台北Táiběi", ["utf8class1"] );
+	
+	t( "Escaped Class", ".foo\\:bar", ["foo:bar"] );
+	t( "Escaped Class", ".test\\.foo\\[5\\]bar", ["test.foo[5]bar"] );
+	t( "Descendant scaped Class", "div .foo\\:bar", ["foo:bar"] );
+	t( "Descendant scaped Class", "div .test\\.foo\\[5\\]bar", ["test.foo[5]bar"] );
+	t( "Child escaped Class", "form > .foo\\:bar", ["foo:bar"] );
+	t( "Child escaped Class", "form > .test\\.foo\\[5\\]bar", ["test.foo[5]bar"] );
 });
 
 test("multiple", function() {