需要在mxml文件中添加下面代码中的红色部分：
mxml完整源码如下：
<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
xmlns:mx="library://ns.adobe.com/flex/mx" minWidth="955" minHeight="600" initialize="application1_initializeHandler(event)">
<fx:Script>
<![CDATA[
import mx.controls.Alert;
import mx.events.FlexEvent;
import flash.system.Security;
Security.allowDomain("*");
Security.allowInsecureDomain("*");
protected function application1_initializeHandler(event:FlexEvent):void
{
// TODO Auto-generated method stub
if(ExternalInterface.available)
{
ExternalInterface.addCallback("getFlexMsg",getMsgFromFlex);
}
}
public function getMsgFromFlex():void
{
btnOK.label="js调用flex成功";
}
protected function button1_clickHandler(event:MouseEvent):void
{
// TODO Auto-generated method stub
var msg:String=ExternalInterface.call("jsFun");
mx.controls.Alert.show(msg);
}
]]>
</fx:Script>
<fx:Declarations>
<!-- 将非可视元素（例如服务、值对象）放在此处 -->
</fx:Declarations>
<s:Button id="btnOK" x="268" y="103" width="137" label="按钮" click="button1_clickHandler(event)"/>
</s:Application>
JS调用代码如下：
function jsFun() //被flex中的as方法调用
{
return "来自js";
}
function getFlexMsg() //调用flex中的as方法
{
var msg=document.getElementById("JSandFlex").getFlexMsg(); //说明：JSandFlex是html文件中flash builder生成的swf对象的id，getFlexMsg是在flex中注册的可被js调用的as方法别名
}
以上js代码可直接放在index.template.html的<head></head>内，也可放在单独的文件中然后在index.template.html中引用.