Specify a Flex user-interface control as the value of the source property
<?xml version="1.0"?> <mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"> <mx:ZipCodeValidator id="zipV" source="{myZip}" property="text" /> <mx:TextInput id="phoneInput" /> <mx:TextInput id="myZip" /> </mx:Application>