<input type="file"> limit selectable files by extensions

Question

How can someone limit the files that can be selected with the input type="file" element by extensions?

I already know the accept attribute, but in chrome it does limit the files by the last MIME Type defined (in this case "gif") and FF4 does not even limit anything.

<input type="file" accept="image/jpg, image/gif">

Am I doing anything wrong or is there another way?

Answer 1

Honestly, the best way to limit files is on the server side. People can spoof file type on the client so taking in the full file name at server transfer time, parsing out the file type, and then returning a message is usually the best bet.