$url = 'http://www.baidu.com';

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL,$url);
// 不要http header 加快效率
curl_setopt($curl, CURLOPT_HEADER, 0);
// https请求 不验证证书和hosts
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false); 
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);

curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
$res = curl_exec($ch); //已经获取到内容,没有输出到页面上.
curl_close($ch);