<?xml version="1.0" encoding="utf-8"?> <mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute">     <mx:Button x="144" y="190" label="Button">         <mx:click>             <![CDATA[                 import mx.controls.Alert;                 Alert.show("click");             ]]>         </mx:click>         <mx:focusOut>             <![CDATA[                 import mx.controls.Alert;                 Alert.show("focusOut");             ]]>         </mx:focusOut>     </mx:Button> </mx:Application> 对优化代码很有好处