Browser Plug-In Detection with JavaScript

Because there are clearly times when it makes sense to use a plug-in, the question arises of how to deal with those who don't have the required plug-in installed. As Web developers, we have several choices. One option is to do nothing and simply serve the plug-in-dependent content. The trouble is that those that don't have the required plug-in will get a rather disturbing page with a broken plug-in icon where your beautiful multimedia should be.

Another option is to give visitors a choice between the plug-in version and the static HTML version of each page...