mvc 3.0 ajax.beginForm 跳转 是怎么会是

前台代码：

<script src="../../Scripts/MicrosoftAjax.js" type="text/javascript"></script>
<script src="../../Scripts/MicrosoftMvcAjax.js" type="text/javascript"></script>
<script src="../../Scripts/jquery-1.5.1.js" type="text/javascript"></script>

@using (Ajax.BeginForm("GetDate", "Ajax",     new AjaxOptions() {    

     Confirm = "确定吗？",     

    HttpMethod = "post",      

   InsertionMode = InsertionMode.InsertAfter,    

     UpdateTargetId = "ajaxid",            }))

{     <input type="text" name="txtname" />     <br /> <input type="submit" value="提交" /> }

<div id="ajaxid"> </div>

后台：

  public ActionResult GetDate()
        {
            return Content(DateTime.Now.ToString());
        }