How can I get file extensions with JavaScript?

Newer Edit: Lots of things have changed since this question was initially posted – there’s a lot of really good information in wallacer’s revised answer as well as VisioN’s excellent breakdown

---

Edit: Just because this is the accepted answer; wallacer’s answer is indeed much better:

return filename.split('.').pop();

---

My old answer:

return /[^.]+$/.exec(filename);

Should do it.

Edit: In response to PhiLho’s comment, use something like:

return (/[.]/.exec(filename)) ? /[^.]+$/.exec(filename) : undefined;