The main thing is telling the browser that nothing has happened after clicking the image (button).

In fact, the server did load your cgi script that called your excel thing. But you need to tell the browser that the screen is not going to update with anything. So, it is all going to look the same as before clicking.

So, use CGI; and send the following header after leaving your cgi script...

print $cgi->header(  -status=>'204 No Response',
             -expires=>'+3d',
                )  if ($ENV{HTTP_REFERER});
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