tech-island.com

 function is_online($uin) {
  if (!is_numeric($uin)) return FALSE;
 
  $fp = fsockopen('status.icq.com', 80, &$errno, &$errstr, 8);
  if (!$fp) return FALSE;
  $request = "GET /online.gif?icq=".$uin."&img=5 HTTP/1.0rn"
              ."Host: status.icq.comrn"
      ."Connection: closernrn";
    fputs($fp, $request);
 
    do {
      $response = fgets($fp, 1024);
#      echo $response,'<br />';
    } while (!feof($fp) && !stristr($response, 'Location'));
 
    fclose($fp);
 
    if (strstr($response, 'online1.gif')) return 'online';
    if (strstr($response, 'online0.gif')) return 'offline';
    if (strstr($response, 'online2.gif')) return 'disabled';
    return FALSE;
}

<?
$test = url_validate("<a href="http://www.tech-island.com/");" target="blank">http://www.tech-island.com/");</a>
echo "test=[$test]";
?>

/*
<ul>
<li> @return status code or HTTP request</li>
<li> @param  string $link</li>
<li> @desc   Überprüft die angegeben URL auf Erreichbarkeit und</li>
<li>         liefert den HTTP Code oder DNS-Error zurück</li>
<li>/</li>
</ul>
function url_validate($link)
{
  // Parse URL and set default values if neccesary
  $url_parts = parse_url( $link );
  if (empty($url_parts["host"]))
    return(false);
  if (!empty($url_parts["path"]))
    $documentpath = $url_parts["path"];
  else
    $documentpath = "/";
  if (!empty( $url_parts["query"]))
   $documentpath .= "?" . $url_parts["query"];
 
  // Get Host and Port from URL, Port 80 default
  $host = $url_parts["host"];
  $port = $url_parts["port"];
 
  if (empty($port))
    $port = "80";
 
  // Now (HTTP-)GET $documentpath at $host";
  $socket = fsockopen( $host, $port, $errno, $errstr, 30 );
  if (!$socket)
  {
    // If socket can't bew connected there's a DNS-Error
    $status = "dns-error";
  }
  else
  {
    // Get Status Code
    fwrite ($socket, "HEAD ".$documentpath." HTTP/1.0rnHost: $hostrnrn");
    $http_response = fgets($socket, 30);
 
    if (ereg("200 OK", $http_response, $regs ))
      $status = "200";
    elseif (ereg("404", $http_response, $regs ))
      $status = "404";
    elseif (ereg("30", $http_response, $regs))
      $status = "30*";
    else
      $status = $http_response;
 
    fclose($socket);
  }
  return ($status);
}