Handle changing form attributes correctly when there is a child element with...

Handle changing form attributes correctly when there is a child element with the same name.  Fixes #4299

src/attributes.js

@@ -218,7 +218,13 @@ jQuery.extend({
 					if ( name == "type" && /(button|input)/i.test(elem.nodeName) && elem.parentNode ) {
 						throw "type property can't be changed";
 					}
-					elem[ name ] = value;
+					// browsers index elements by id/name on forms, give priority to attributes.
+					if( jQuery.nodeName( elem, "form" ) ) {
+						// convert the value to a string (all browsers do this but IE) see #1070
+						elem.setAttribute( name, "" + value );
+					} else {
+						elem[ name ] = value;
+					}
 				}
 
 				// browsers index elements by id/name on forms, give priority to attributes.

test/unit/attributes.js

 module("attributes");
 
 test("attr(String)", function() {
-	expect(27);
+	expect(28);
 	
 	// This one sometimes fails randomally ?!
 	equals( jQuery('#text1').attr('value'), "Test", 'Check for value attribute' );
@@ -18,6 +18,7 @@ test("attr(String)", function() {
 	equals( jQuery('#name').attr('name'), "name", 'Check for name attribute' );
 	equals( jQuery('#text1').attr('name'), "action", 'Check for name attribute' );
 	ok( jQuery('#form').attr('action').indexOf("formaction") >= 0, 'Check for action attribute' );
+	ok( jQuery('#form').attr('action','newformaction').attr('action').indexOf("newformaction") >= 0, 'Check that action attribute was changed' );
 	equals( jQuery('#text1').attr('maxlength'), '30', 'Check for maxlength attribute' );
 	equals( jQuery('#text1').attr('maxLength'), '30', 'Check for maxLength attribute' );
 	equals( jQuery('#area1').attr('maxLength'), '30', 'Check for maxLength attribute' );