如何使用脚本模仿登陆过程

查看他的登陆页面的代码， 看他提交到哪个页面， 变量是什么。
代码如下:
<form method="post" action="login.jsp">
<table align="center" width="40%" style="FONT-SIZE: 12px" border="0" cellpadding="0" cellspacing="2">
  <tr>
    <td width="30%" align="right" bgcolor="#0073AA" style="FONT-SIZE: 12px;color:#ffffff">name:</td>
    <td width="70%"><input type="text" size="30" name="username"></td>
  </tr>
  <tr>
    <td width="30%" align="right" bgcolor="#0073AA" style="FONT-SIZE: 12px;color:#ffffff">password:</td>
    <td width="70%"><input type="password" size="32" name="passwd"></td>
  </tr>
  <tr>
    <td colspan="2" align="right">
      <input type="submit" name="submit" value="Login"> 
      <input type="button" name="submit" value="regest" onclick="location.href='regest.jsp'">
    </td>
  </tr>
</table>
</form>

很明显， 如果你要登陆， 你需要把username, passwd, submit这几个变量post到login.jsp， 而且submit=Login
用以下代码：
代码如下:
<?php
        $postData = "username=your_name&password=your_password&Submit=Login";
        $posturl = "http://......../../login.jsp";

        $postUrl = parse_url($posturl);
        $host = $postUrl[host] ? $postUrl[host] : "";
        $port = $postUrl[port] ? $postUrl[port] : 80;
        $path = $postUrl[path] ? $postUrl[path] : "/";



        $fsp = fsockopen($host, $port, &$errno, &$errstr, 30);
        if(!$fsp){
                print "\nopen socket failed\n";
        }else{
                fwrite($fsp, "POST ".$path." HTTP/1.1\r\n");
                fwrite($fsp, "Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/x-shockwave-flash, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, */*\r\n");
                fwrite($fsp, "Accept-Language: zh-cn\r\n");
                fwrite($fsp, "Content-Type: application/x-www-form-urlencoded\r\n");
                fwrite($fsp, "User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; Maxthon)\r\n");
                fwrite($fsp, "Host:".$host."\r\n");
                fwrite($fsp, "Content-Length: ".strlen($postData)."\r\n\r\n");
                fwrite($fsp, $postData);

                $resp = "";
                do{
                        if(strlen($out=fread($fsp, 1024)) == 0) break;
                        $resp .= $out;
                }while(true);

                echo "<br><br>".nl2br($resp);

                fclose($fsp);

        }
?>