Js模拟VB的Microsoft Common Dialog Control控件中的ShowSave的功能

<HTML>
<HEAD>
<TITLE> New Document </TITLE>
<META NAME="Generator" CONTENT="EditPlus">
<META NAME="Author" CONTENT="">
<META NAME="Keywords" CONTENT="">
<META NAME="Description" CONTENT="">
<SCRIPT LANGUAGE="JavaScript">
<!--
function saveas()
{
cd.showsave(); var filename = cd.filename; if(filename.length>0)
{
alert(filename);
}
}
//-->
</SCRIPT>
</HEAD><BODY>
<OBJECT ID="cd" WIDTH="" HEIGHT="" CLASSID="CLSID:F9043C85-F6F2-101A-A3C9-08002B2F49FB">
</OBJECT><input type=button onclick="saveas()" value="save">
</BODY>
</HTML>