<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2008/08/29/validating-email-addresses-using-the-emailvalidator-class-in-flex/ -->
<mx:Application name="EmailValidator_validate_test"
        xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        backgroundColor="white">

    <mx:Script>
        <![CDATA[
            import mx.controls.Alert;
            import mx.events.ValidationResultEvent;

            private function emailValidator_valid(evt:ValidationResultEvent):void {
                textInput.errorString = "";
                message.text = "";
                Alert.show(textInput.text, "You entered a valid email address:");
            }

            private function emailValidator_invalid(evt:ValidationResultEvent):void {
                textInput.errorString = evt.message;
                message.text = evt.message;
            }
        ]]>
    </mx:Script>

    <mx:EmailValidator id="emailValidator"
            valid="emailValidator_valid(event);"
            invalid="emailValidator_invalid(event);"
            source="{textInput}"
            property="text"
            trigger="{btn}"
            triggerEvent="click" />

    <mx:Form defaultButton="{btn}">
        <mx:FormItem label="email address:"
                direction="horizontal">
            <mx:TextInput id="textInput"
                    focusAlpha="0.0" />
            <mx:Button id="btn"
                    label="validate" />
        </mx:FormItem>
    </mx:Form>
    <mx:Label id="message" />

</mx:Application>