使用隐藏域input，提交表单未设置默认值，提交报错400

1、 html表单如下：

<form action="operate_addenterandexit.html" method="post">
<div id="hidden" >
	<label>班组/个人进退场记录</label>
	<span>
		<select name="type">
			<option value="2" <c:if test="${type==2}">selected</c:if> style="width:60px">班组</option>
			<option value="1" <c:if test="${type==1}">selected</c:if> style="width:60px">个人</option>
		</select>
	</span>
</div>
<div>
	<label>班组名称</label>
	<span>
		<select name="teamName">
			<c:forEach items="${teamList}" var="team">
				<option value="${team.name}">${team.name}</option>
			</c:forEach>
		</select>
	</span>
</div>
<div>
	<label>姓名</label>
	<span><input name="name" type="text"/></span>
</div>
<div>
	<label>联系方式</label>
	<span><input name="cId" type="text"/></span>
</div>
<div>
	<label>性质</label>
	<span>
		<select id="eqtime" name=""><!-- 目前这个字段自用来通过js控制前端的页面 -->
			<option value="">进场</option>
			<option value="">退场</option>
		</select>
	</span>
</div>
<div class="enter">
	<label>进场时间</label>
	<span><input name="startTime" type="text" value=""/></span>
</div>
<div class="quit">
	<div>
		<label>退场时间</label>
		<span><input name="endTime" type="text" value="" /></span>
	</div>
	<div class="star">
		<label>技能</label>
		<ul>
			<li data-star=-5><img src="resource/images/u663.fw.png" alt="" /></li>
			<li data-star=-2><img src="resource/images/u663.fw.png" alt="" /></li>
			<li data-star=0><img src="resource/images/u663.fw.png" alt="" /></li>
			<li data-star=2><img src="resource/images/u663.fw.png" alt="" /></li>
			<li data-star=5><img src="resource/images/u663.fw.png" alt="" /></li>
		</ul>
		<form action