打击回看看，为什么post过来的数据为空

打击来看看，为什么post过来的数据为空

<form method="post" action="/Thinkphp/admin.php/User/do_login" id="form1" name='form1'>
            <div class="container">
                <div class="content">
                    <div class="bt"><h1>WELCOME</h1><span>即将进入后台管理系统……</span></div>
                    <div class="logo"></div>
                    <div class="name">
                        <ul>
                            <li><span>用户名：</span><input name="txtUserName" type="text" id="txtUserName" class="login_input required" /></li>
                            <li><span>密  码：</span><input name="txtUserPwd" type="password" id="txtUserPwd" class="login_input required" /></li>
                            <li class="yzm"><span>验证码：</span><input name="txtCode" type="text" maxlength="6" id="txtCode" class="login_input required" />
                                &nbsp;&nbsp;&nbsp;
                                <img src="/Thinkphp/momuadmin.php/Public/code"   alt="点击切换验证码" title="点击切换验证码" style=" margin-top:5px; vertical-align:top;cursor:pointer;"onclick="ToggleCode(this, '/Thinkphp/momuadmin.php/Public/code');
                                        return false;"  />
                            </li>
                        </ul>
                        <div class="ok">
                            <input type="submit" name="btnSubmit" value="登 录" id="btnSubmit" class="login_btn" /><br/>
                        </div><br/>
                    </div>
                </div>
            </div>
            <div class="footer">
                <div class="footbox">Copyright 1998 - 2013 MOMU. All Rights Reserved. <a href="#target="_blank" style="color:#FFF;"</a> 版权所有</div>
            </div>
            </div>
        </form>

 public function do_login() {
        $username = $_POST['txtUserName'];
        $userpwd = $_POST['txtUserPwd'];
        $code = $_POST['txtCode'];
        if ($code==$_SESSION['verify']) {
            $m = M('Manger');
            $where['username'] = $username;
            $where['userpwd'] = md5($userpwd);
            $i = $m->where($where)->count();
            if ($i > 0) {
                $this->redirect(__URL__ / main);
            } else {
                $this->error('用户名或密码错误');
            }
        } else {
            var_dump($_POST).'</br>';
            //var_dump($_SESSION['verify']);
            //$this->error('验证码错误');
        }
    }

每次都是$_post为空，求教这是为什么
------解决思路----------------------
代码没有问题在if里面echo['txtUserName']
在else里面echo['txtUserPwd']看看输出什么
------解决思路----------------------

<div class="footbox">Copyright 1998 - 2013 MOMU. All Rights Reserved. <a href="#target="_blank" style="color:#FFF;"</a> 版权所有</div>

这里修改为

<div class="footbox">Copyright 1998 - 2013 MOMU. All Rights Reserved. <a href="#" target="_blank" style="color:#FFF;"></a> 版权所有</div>

起了两个文件测试，是可以post并接收数据的。

<meta http-equiv="content-type" content="text/html; charset=utf-8">
<form method="post" action="server.php" id="form1" name='form1'>
    <div class="container">
        <div class="content">
            <div class="bt"><h1>WELCOME</h1><span>即将进入后台管理系统……</span></div>
            <div class="logo"></div>
            <div class="name">
                <ul>
                    <li><span>用户名：</span><input name="txtUserName" type="text" id="txtUserName" class="login_input required" /></li>
                    <li><span>密  码：</span><input name="txtUserPwd" type="password" id="txtUserPwd" class="login_input required" /></li>
                    <li class="yzm"><span>验证码：</span><input name="txtCode" type="text" maxlength="6" id="txtCode" class="login_input required" />
                        &nbsp;&nbsp;&nbsp;
                        <img src="/Thinkphp/momuadmin.php/Public/code"   alt="点击切换验证码" title="点击切换验证码" style=" margin-top:5px; vertical-align:top;cursor:pointer;"onclick="ToggleCode(this, '/Thinkphp/momuadmin.php/Public/code');
                                return false;"  />
                    </li>
                </ul>
                <div class="ok">
                    <input type="submit" name="btnSubmit" value="登 录" id="btnSubmit" class="login_btn" /><br/>
                </div><br/>
            </div>
        </div>
    </div>
    <div class="footer">
        <div class="footbox">Copyright 1998 - 2013 MOMU. All Rights Reserved. <a href="#" target="_blank" style="color:#FFF;"></a> 版权所有</div>
    </div>
    </div>
</form>

server.php

<?php
$username = $_POST['txtUserName'];
$userpwd = $_POST['txtUserPwd'];
$code = $_POST['txtCode'];

echo $username;
echo $userpwd;
echo $code;
?>