PHP简单检测网址是否能够正常打开的方法

<?php
 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);
}
echo "判断链接：".httpcode('https://www.bingdou.com.cn');
?>

如果显示为200则正常，如果显示其它值表示不正常；$timeout后面的3是设置超时秒数。