代码点火器:为什么代码点火器认为表单是get请求而不是post请求

这里是形式：

<?php echo form_open('locker_settingstwo/processform', array('class' => 'form-horizontal')); ?>
        <div class = "lockersettingstwodiv"> 
            <h2><?php echo $this->session->userdata('labelname'); ?></h2>
            <p> Control who can view/ReGemz the collection in this locker </p>
            <input type = "text" name = "testing" value = "" />
            <input type="radio" name="permission" value="1" /> Public - Others can view/edit this locker<br/>
            <input type="radio" name="permission" value="2" /> Me Only - Only you can view/edit this locker<br/>
            <input type="radio" name="permission" value="custom" /> Custom - Locked to everyone, meaning only friends I choose can view/edit this locker<br/>
        </div>
            <input type="submit" name = "Next" value="Next" class="btn btn-large btn-primary" style="margin-left: 0px; margin-top: 14px" />
            <input type="submit" name = "Cancel" value="Cancel" class="btn btn-large btn-primary" style="margin-left: 0px; margin-top: 14px" />
    <?php echo form_close(); ?>  

现在，当我打印$_SERVER['REQUEST_METHOD']时，它说的是GET，而不是POST。。。为什么？

这是表单发送到的控制器方法：

function processform() 
{
    echo $_SERVER['REQUEST_METHOD'];
}