How to pull the file name from a url using javascript/jquery?

A certain variable might contain a relative path or an absolute path. Either way, I need to be able to pull the filename from the variable:

http://www.somesite.com/dir1/dir2/filename.gif
/dir1/dir2/filename.gif

The directory structure is also arbitrary. So basically given either of the url's above (with arbirtrary directory structure) I need to pull 'filename.gif'. Thanks in advance

var index = yourstring.lastIndexOf("/") + 1;
var filename = yourstring.substr(index);

Shorter way

var filename = window.location.href.substr(window.location.href.lastIndexOf("/")+1);

var filename = url.match(/.*\/(.*)$/)[1];

var filename= url.split('/').pop()

I'd use a regular expression.

[^/]*$

It selects everything after the last slash until the end. You can expand it to select the extension separately:

/([^/]*?)(\.[^\./]*)?$