讲述了php判断是否连接上网络的方法。

<?php
function varify_url($url){ 
$check = @fopen($url,"r"); 
if($check){
$status = true; 
}else{
$status = false; 
} 
return $status; 
}

接着在需要的地方直接调用即可。如下:

$url = "http://www.youkud.com"; 
if(varify_url($url)){ 
echo "<div>Congratulation ! Your URL <a href=$url>$url</a> : is <b>valid </b></div>"; 
}else{ 
echo "<div>Error ! Your URL : <a href=$url>$url</a> is <b>invalid </b></div>"; 
}