<?php
   function url_exists($url) {
       $a_url = parse_url($url);
       if (!isset($a_url['port'])) $a_url['port'] = 80;
       $errno = 0;
       $errstr = ''
       $timeout = 30;
       if(isset($a_url['host']) && $a_url['host']!=gethostbyname($a_url['host'])){
           $fid = fsockopen($a_url['host'], $a_url['port'], $errno, $errstr, $timeout);
           if (!$fid) return false;
           $page = isset($a_url['path'])  ?$a_url['path']:''
           $page .= isset($a_url['query'])?'?'.$a_url['query']:''
           fputs($fid, 'HEAD '.$page.' HTTP/1.0'."\r\n".'Host: '.$a_url['host']."\r\n\r\n");
           $head = fread($fid, 4096);
           fclose($fid);
           return preg_match('#^HTTP/.*\s+[200|302]+\s#i', $head);
       } else {
           return false;
       }
   }
$a = "[img]http://blog.bojack.idv.tw/my_files/1.JPG[/img]";
echo url_exists($a);
?>