function make_clickable($text){ 
   $ret = " " . $text; 
   $ret = preg_replace("#([\n ])([a-z]+?)://([^,\t \n\r]+)#i", "\\1<a href=\"\\2://\\3\" target=\"_blank\">\\2://\\3</a>", $ret); 
   $ret = preg_replace("#([\n ])www\.([a-z0-9\-]+)\.([a-z0-9\-.\~]+)((?:/[^,\t \n\r]*)?)#i", "\\1<a href=\"http://www.\\2.\\3\\4\" target=\"_blank\">www.\\2.\\3\\4</a>", $ret); 
   $ret = preg_replace("#([\n ])([a-z0-9\-_.]+?)@([\w\-]+\.([\w\-\.]+\.)?[\w]+)#i", "\\1<a href=\"mailto:\\2@\\3\">\\2@\\3</a>", $ret); 
   $ret = substr($ret, 1); 
   return($ret);}

Used to convert URLs in a string into links

make_clickable($text)

php, text

PHP