How to setHomePage in AS3?

programming flash
1

I try to call Javascript in AS3,I want to setHomePage
–as3 code–

 
private function onMouseClick(event:MouseEvent):void{
ExternalInterface.call("fonk1");
}

–html code–

 
<LINK REL="stylesheet" HREF="/workshop/samples/samples.css" TYPE="text/css">
<STYLE>
@media all {
   IE\:HOMEPAGE {behavior:url(#default#homepage)}
}
</STYLE>
<SCRIPT Language="Javascript">
function fonk1(){
alert('1');
document.all.oHomePage.setHomePage(oHomeHref.value);
alert('2');
event.returnValue = false;
}
</SCRIPT>
</HEAD>
<BODY>
<DIV class="body">
<IE:HOMEPAGE ID="oHomePage" />
<label for="oHomeHref">Homepage [URL:</label](http://forums.adobe.com/%3C/label)>
<input type=text id="oHomeHref" size="30" value="http://www.microsoft.com/">
<p>
<input type=button value="Set" onclick="fonk1();"> Set your homepage to the URL entered in the text field.
<P>
<P>
</DIV>
<div id="flashContent">
   <object classid="clsid:d27cdb6e-ae6d-11cf-96b8-444553540000" width="550" height="400" id="externalInterface" align="middle">
    <param name="movie" value="Demo.swf" />
    <param name="quality" value="high" />
    <param name="bgcolor" value="#ffffff" />
    <param name="play" value="true" />
    <param name="loop" value="true" />
    <param name="wmode" value="window" />
    <param name="scale" value="showall" />
    <param name="menu" value="true" />
    <param name="devicefont" value="false" />
    <param name="salign" value="" />
    <param name="allowScriptAccess" value="sameDomain" />
    <!--[if !IE]>-->
    <object type="application/x-shockwave-flash" data="externalInterface.swf" width="550" height="400">
     <param name="movie" value="Demo.swf" />
     <param name="quality" value="high" />
     <param name="bgcolor" value="#ffffff" />
     <param name="play" value="true" />
     <param name="loop" value="true" />
     <param name="wmode" value="window" />
     <param name="scale" value="showall" />
     <param name="menu" value="true" />
     <param name="devicefont" value="false" />
     <param name="salign" value="" />
     <param name="allowScriptAccess" value="sameDomain" />
    <!--<![endif]-->
     <a href="http://www.adobe.com/go/getflash">
      <img src="[http://www.adobe.com/images/shared/download_buttons/get_flash_player.g if](http://www.adobe.com/images/shared/download_buttons/get_flash_player.gif)" alt="Get Adobe Flash player" />
     </a>
    <!--[if !IE]>-->
    </object>
    <!--<![endif]-->
   </object>
  </div>

above code which except swf code is from MIcrosoft MSDN, I run above code in IE8,when I click Set button,it can alert(‘1’),and set HomePage,and alert(‘2’). It runs well,but when I click swf,it also can alert(‘1’),but I don’t see it set HomePage! and I don’t see alert(‘2’). Where is wrong? Why Set button call call setHomePage and swf can’t call setHomePage? Is there limits between HTML and SWF? I am puzzled with HomePage for a very long time. How to correct above code?

Thanks