Use Email validator
<?xml version="1.0" encoding="utf-8"?> <mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute"> <mx:EmailValidator id="emailValidator" source="{emailTextInput}" property="text" requiredFieldError="Please enter your email. " triggerEvent="change" /> <mx:TextInput id="emailTextInput" /> </mx:Application>