PHPでWebページのコンテンツを取得する方法

<?php 
$url = "http://www.jb51.net"; 
$contents = file_get_contents($url); 
//如果出现中文乱码使用下面代码 
//$getcontent = iconv("gb2312", "utf-8",$contents); 
echo $contents; 
?>

<?php 
$url = "http://www.jb51.net"; 
$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; 
?>

<?php 
$handle = fopen ("http://www.jb51.net", "rb"); 
$contents = ""; 
do { 
$data = fread($handle, 1024); 
if (strlen($data) == 0) { 
break; 
} 
$contents .= $data; 
} while(true); 
fclose ($handle); 
echo $contents; 
?>