What's the best way to detect that Adobe Acrobat Reader is installed from a browser?

Question

What's the best way to detect that Adobe Acrobat Reader is installed from a web browser? I'm assuming it would have to be done on the client-side (I don't think Adobe adds any user-agent strings). Preferably in JavaScript and in Internet Explorer, although it would be nice if it could also be done in FireFox, Safari, etc...

Answer 1

This article from the Adobe website should get you what you need.

EDIT

In testing this it isn't 100% though, as I have acrobat, but it doesn't detect it in IE 6.

Answer 2

Also note that, even if someone does not have the Acrobat Reader plugin, he might still be able to read PDF files (for instance, by telling the browser to launch an external reader such as kpdf). So allow the user to download the PDF even if the plugin cannot be found. Not to mention the people with Javascript disabled (or NoScript users).