EasyUI Datebox 日期验证之开始日期小于结束时间

<div style="width:65px;"><label>选择时间：</label></div>
<div style="width:100px;" id="startstime">
   <div class="easyui-datebox" name="data" id="startdate" style="height:26px;width:100px "></div>
 </div>
 <divstyle="width:110px;" id="endtime">
   -
  <div class="easyui-datebox" type="text" name="data" id="enddate" style="height:26px;width:100px " validtype="end"></div>
</div>

//验证开始时间小于结束时间 
$.extend($.fn.validatebox.defaults.rules, {
  end: {
    validator: function (value, param) {
      var startdate = $("#startstime input").val();
      var starttmp = new date(startdate.replace(/-/g, "/"));
      var endtmp = new date(value.replace(/-/g, "/"));
      return starttmp <= endtmp;
    },
    message: '结束时间要大于开始时间！'
  }
})