<?php
function urlExists($url=NULL)
{
    if($url == NULL) return false;
    $ch = curl_init($url);
    curl_setopt($ch, CURLOPT_TIMEOUT, 5);
    curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 5);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    $data = curl_exec($ch);
    $httpcode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
    curl_close($ch);
    return $httpcode;
}
echo urlExists("https://cert.vatsim.net/vatsimnet/idstatus.php?cid=1346088");
?>