模拟POST方法提交表单三个要点

1. 声明是post方法

   curl_setopt($curl,CURLOPT_POST,1);

2. 表单提交的数据

   $data = "username=zhangsan&sex=male";
   curl_setopt($curl,CURLOPT_POSTFIELDs,$data);

3. POST提交的头信息

   curl_setopt($curl,CURLOPT_HTTPHEADER,
   array("application/x-www-form-urlencoded;charset=utf-8","Content-length:".strlen($data)));