file_get_contents获取不到网页内容的解决方法

file_get_contents获取不到网页内容的解决方法，需要的朋友可以参考一下

 <?php 
$url = "http://jb51.net/index.html"; 
$ch = curl_init(); 
$timeout = 5; 
curl_setopt($ch, CURLOPT_URL, $url); 
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); 
curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, $timeout); 
//在需要用户检测的网页里需要增加下面两行 
//curl_setopt($ch, CURLOPT_HTTPAUTH, CURLAUTH_ANY); 
//curl_setopt($ch, CURLOPT_USERPWD, US_NAME.":".US_PWD); 
$contents = curl_exec($ch); 
curl_close($ch); 
echo $contents; 
?>