Check for Flash with PHP

[Mistah_Roth]

I need to check if a user has Flash, and if they do include a file, if not, then do nothing. Any idea how to check this in PHP?

[konsu]

php is a server side system. browser extensions for flash are client side components. macromedia.com has help on how to detect flash plugins in client side code. but php being on the server side has nothing to do with it.