How to nest OR statements in JavaScript?

Question

Currently I am creating a filemanager.

What I want is to check if the user has selected a video file. The file can be mov, f4v, flv<

Answer 1

Kinda nice way is this:

var exts = {
     "mov" : null,
     "f4v" : null,
     "flv" : null,
     "mp4" : null,
     "swf" : null,
}

if(ext in exts){
    // world peace
}