detecting FireFox4 browser

How to detect FireFox4 or any updated versions of FireFox, to include specific stylesheet? Note开发者_如何学C: FF4 and FF5 gives font-size too small when printed. on screen its fine(FF3.0 to FF5).

You need to inspect the user agent string. How you do that wil depend on what technique you wish to use and what platform you are on. In PHP you can inspect the value of $_SERVER['HTTP_USER_AGENT'], or you can do it using jQuery as Eamorr says. It is also possible a number of other ways, you'll have to tell us more about your setup.