PHP Function to get extension of a file.

Here is a simple function which returns the extension of the file.

           function getExtension($str)

{

                        $i = strrpos($str,".");

                        if (!$i) { return ""; }

                        $l = strlen($str) - $i;

                        $ext = substr($str,$i+1,$l);

                        return $ext;

}