Using EmailValidator
<?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="An at sign (@) is missing in your e-mail address." /> <mx:TextInput id="emailTextInput" /> </mx:Application>