求助：如何获取iframe里嵌套的多媒体文本框中的内容


<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML XMLNS:IE; xmlns:MSHelp=http://msdn.microsoft.com/msHelp>
<IE:DOWNLOAD ID="oDownload" STYLE="behavior:url(#default#download)" /><SCRIPT>
//<!--
function onDownloadDone(s) {
alert(s);
}
function f1()
{
oDownload.startDownload(document.all.htmeditor.src, onDownloadDone)
}//-->
</SCRIPT>
<input type="button" value="oooo" onclick= f1() ID=Button1>
<iframe id=htmeditor name=htmeditor src="/system/_content/editor/webberedit.htm"  width=450 height=335>
        </iframe>