向服务器提交POST表单并保存结果的原理，可做刷票系统。

        $str="username=test&password=123"
        $fp=fsockopen("www.123cha.com",80);
        fputs($fp,"POST /postal/index.php HTTP/1.1 ");
        fputs($fp,"Host:www.123cha.com ");
        fputs($fp,"Content-Type:application/x-www-form-urlencoded ");
        fputs($fp,"Content-Length:".strlen($str)." ");
        fputs($fp,$str." ");
        while(!feof($fp))
        {
                $http_response.=fgets($fp,128);
        }
        fclose($fp);