Microoptimization in jQuery.attr and remove the redundancy of return …

…undefined

src/attributes.js

@@ -177,7 +177,7 @@ jQuery.fn.extend({
 					ret == null ? "" : ret;
 			}
 
-			return undefined;
+			return;
 		}
 
 		isFunction = jQuery.isFunction( value );
@@ -302,15 +302,15 @@ jQuery.extend({
 
 		// don't get/set attributes on text, comment and attribute nodes
 		if ( !elem || nType === 3 || nType === 8 || nType === 2 ) {
-			return undefined;
+			return;
 		}
 
 		if ( pass && name in jQuery.attrFn ) {
 			return jQuery( elem )[ name ]( value );
 		}
 
 		// Fallback to prop when attributes are not supported
-		if ( !("getAttribute" in elem) ) {
+		if ( typeof elem.getAttribute === "undefined" ) {
 			return jQuery.prop( elem, name, value );
 		}
 
@@ -327,7 +327,7 @@ jQuery.extend({
 
 			if ( value === null ) {
 				jQuery.removeAttr( elem, name );
-				return undefined;
+				return;
 
 			} else if ( hooks && "set" in hooks && notxml && (ret = hooks.set( elem, value, name )) !== undefined ) {
 				return ret;
@@ -439,7 +439,7 @@ jQuery.extend({
 
 		// don't get/set properties on text, comment and attribute nodes
 		if ( !elem || nType === 3 || nType === 8 || nType === 2 ) {
-			return undefined;
+			return;
 		}
 
 		notxml = nType !== 1 || !jQuery.isXMLDoc( elem );