Reworked the attribute selection code to be able to select false-y values - and added some tests to verify that they work well against expandos.

Author: jeresig

src/selector.js

@@ -564,7 +564,16 @@ var Expr = Sizzle.selectors = {
 			return match.test( elem.className );
 		},
 		ATTR: function(elem, match){
-			var result = Expr.attrHandle[ match[1] ] ? Expr.attrHandle[ match[1] ]( elem ) : elem[ match[1] ] || elem.getAttribute( match[1] ), value = result + "", type = match[2], check = match[4];
+			var name = match[1],
+				result = Expr.attrHandle[ name ] ?
+					Expr.attrHandle[ name ]( elem ) :
+					elem[ name ] != null ?
+						elem[ name ] :
+						elem.getAttribute( name ),
+				value = result + "",
+				type = match[2],
+				check = match[4];
+
 			return result == null ?
 				type === "!=" :
 				type === "=" ?
@@ -574,7 +583,7 @@ var Expr = Sizzle.selectors = {
 				type === "~=" ?
 				(" " + value + " ").indexOf(check) >= 0 :
 				!check ?
-				result :
+				value && result !== false :
 				type === "!=" ?
 				value != check :
 				type === "^=" ?

test/unit/selector.js

@@ -215,7 +215,7 @@ test("child and adjacent", function() {
 });
 
 test("attributes", function() {
-	expect(37);
+	expect(40);
 	t( "Attribute Exists", "a[title]", ["google"] );
 	t( "Attribute Exists", "*[title]", ["google"] );
 	t( "Attribute Exists", "[title]", ["google"] );
@@ -233,6 +233,13 @@ test("attributes", function() {
 
 	t( "for Attribute", "form label[for]", ["label-for"] );
 	t( "for Attribute in form", "#form [for=action]", ["label-for"] );
+
+	jQuery("form input")[0].test = 0;
+	jQuery("form input")[1].test = 1;
+
+	t( "Expando attribute", "form input[test]", ["text1", "text2"] );
+	t( "Expando attribute value", "form input[test=0]", ["text1"] );
+	t( "Expando attribute value", "form input[test=1]", ["text2"] );
 
 	t( "Attribute containing []", "input[name^='foo[']", ["hidden2"] );
 	t( "Attribute containing []", "input[name^='foo[bar]']", ["hidden2"] );