不能访问目标PHP文件中的变量

一开始我写了一个简单的hotel.php

<div role="main" class="ui-content">
        <?php
        $info = $_GET['type'];//works well $info get num= 1;
        ?>
        <h3 class="ui-bar ui-bar-a ui-corner-all">order</h3>
        <div class="ui-body ui-body-a ui-corner-all">
            <form action="sendmail.php" method="get">
                <ul data-role="listview" data-inset="true">
                    <li class="ui-field-contain">
                        <label for="name">name</label>
                        <input type="text" name="name" id="name" vlaue="" data-clear-btn="true">
                    </li>
                    <li class="ui-field-contain">
                        <label for="phone">phone</label>
                        <input type="text" name="phone" id="name2" vlaue="" data-clear-btn="true">
                    </li>
                    <li class="ui-field-contain">
                        <input class="invisible" type="text" name="room_info" value="<?php $_GET['type'];?>">
                        <label for="slider-2">num</label>
                        <input type="range" name="slider-2" id="slider-2" data-mini="true" data-highlight="true" min="1" max="6" value="4" data-clear-btn="true">
                    </li>
                    <li class="ui-field-contain">
                        <label for="arrive-time">a_time</label>
                        <input type="datetime-local" name="arrive-time" id="arrive-time" value="" data-clear-btn="true">
                    </li>
                    <li class="ui-field-contain">
                        <label for="leave-time">b_time</label>
                        <input type="datetime-local" name="leave-time" id="arrive-time" value="" data-clear-btn="true">
                    </li>
                    <li class="ui-body ui-body-b">
                        <fieldset class="ui-grid-a">
                            <div class="ui-block-a"><button type="reset" class="ui-btn ui-corner-all ui-btn-a">reset</div>
                            <div class="ui-block-b"><button type="submit" class="ui-btn ui-corner-all ui-btn-a" data-ajax="false">sbumit</div>
                        <fieldset>
                    </li>
                </ul>
            </form><!--end form-->
        </div>
    </div>

$info = $_GET['type'];工作良好，$info得到正确的值。但是当我点击提交按钮时。

$name=$_GET['name'];
$phone=$_GET['phone'];
$roominfo=$_GET['room_info'];
$num=$_GET['slider-2'];
$a_time=$_GET['arrive-time'];
$b_time=$_GET['leave-time']; 

都得到了正确的信息，除了roominfo为空。这是什么问题">我试过了">但钢不工作