Der hierfür nötige Code sieht so aus: 

<form name="form">
<OBJECT ID="Label1" WIDTH=96 HEIGHT=24
        CLASSID="CLSID:978C9E23-D4B0-11CE-BF2D-00AA003F40D0">
	<PARAM Name="Caption" Value="ActiveX">
</OBJECT>
<script>
<!--
if (document.form.Label1) //ActiveX Object is there
   {document.write("Your Browser does support ActiveX!")}
if (!(document.form.Label1)) //ActiveX is not there
   {document.write("Your Browser does not support ActiveX!")}
//-->
</script>
</form>