Convert a .com or another address to a full-on clickable link

urlhref.php

<?php
/**
 * $url can equal any of the following URL formats:
 * 
 * http://www.domain.com
 * https://www.domain.net
 * http://subdomain.domain.org
 * www.domain.com/folder
 * subdomain.domain.net
 * subdomain.domain.edu/folder/subfolder
 * domain.net
 * domain.com/folder
 */

$html = preg_replace_callback('#(\s|^)((https?://)?(\w|-)+(\.[a-z]{2,3})+(\:[0-9]+)?(?:/[^\s]*)?)(?=\s|\b)#is',
    create_function('$m', 'if (!preg_match("#^(https?://)#", $m[2])) return $m[1]."<a href=\"http://".$m[2]."\" target=\"blank\">".$m[2]."</a>"; else return $m[1]."<a href=\"".$m[2]."\" target=\"blank\">".$m[2]."</a>";'),
    $url);