PHP erkennt, ob die Website normal geöffnet wird

<?php
//设置最大执行时间是 120秒
ini_set(&#39;max_execution_time&#39;,120);
function httpcode($url){
  $ch = curl_init();
  $timeout = 3;
  curl_setopt($ch,CURLOPT_FOLLOWLOCATION,1);
  curl_setopt($ch,CURLOPT_RETURNTRANSFER,1);
  curl_setopt($ch, CURLOPT_HEADER, 1);
  curl_setopt ($ch, CURLOPT_CONNECTTIMEOUT, $timeout);
  curl_setopt($ch,CURLOPT_URL,$url);
  curl_exec($ch);
  return $httpcode = curl_getinfo($ch,CURLINFO_HTTP_CODE);
  curl_close($ch);
}
$check_web = array(
&#39;//www.jb51.net/&#39;,
&#39;http://sc.jb51.net/&#39;,
&#39;http://tools.jb51.net/&#39;,
&#39;http://baike.jb51.net/&#39;,
&#39;http://demo.jb51.net/&#39;,
&#39;http://demo2.jb51.net/&#39;,
);
for($i=0;$i<count($check_web);$i++){
  echo $check_web[$i].&#39; -> &#39;.httpcode($check_web[$i]).&#39;<br>&#39;;
}
?>