Detect if applet is installed?

Hi,

I have a client who has an asp.net web appliction which uses JUpload
(http://www.aspupload.com/jupload.html).

I have the control embedded using an applet tag. It seems that newer
versions of browers have changed, and the javascript i was using to
detect if the applet was installed no longer seems to work. This is
what I have now:

var ctl = document.getElementById( 'UploadCtl' );
var exists;
try {
exists = ctl != null && ctl.object != null && !ctl.isTransferring();
}
catch( ex ) {
exists = false;
}

if ( exists ) { // do stuff } else { // redirect to another page }

This seems to work ok, unless the user declines to run the applet but
Java is installed. In this case nothing happens. If Java isn't
installed at all, the user is properly redirected.

What's the best way to use javascript to redirect if Java isn't there,
or the user declined to run the applet?

Thanks
Andy