asp.net-mvc – MVC 4 Ajax.beginform提交 – 导致完全回发

我正在使用Ajax.BeginForm进行回传验证,它回发整个页面而不仅仅是UpdateTargetID.我已经查看了SO上的其他帖子,但没有找到答案.我已经构建了一个新的MVC4 Internet项目,仅用于测试(VS 2012已经使用’ASP.NET和Web Tools 2012.2’进行了更新).

这是我的代码

调节器

public ActionResult Index() 
{
  var vM = _db.Students.FirstOrDefault(); return View(vM);
}

[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Index(Student vM)
{
  if (ModelState.IsValid)
  { //code if Model valid
    return Json(new { url = Url.Action("About","Controller") });
  }
  ModelState.AddModelError(string.Empty,"AJAX Post");
  return PartialView("Index",vM);
}

视图

@model AJAX_Test.Models.Student
@{ ViewBag.Title = "Student"; }
<script src="~/Scripts/jquery-1.8.2.js"></script>
<script src="~/Scripts/jquery.unobtrusive-ajax.js"></script>
<script type="text/javascript">  var onSuccess = function (result)
{
  if (result.url) { window.location.href = result.url; } 
}
  // when server returns JSON object containing an url property redirect the browser    </script>
<h1>@ViewBag.Title</h1>
<div id="IDXForm">
@using (Ajax.BeginForm("Index",new AjaxOptions() { UpdateTargetId = "IDXForm",OnSuccess = "onSuccess",HttpMethod = "Post" }))
{   
  @Html.AntiForgeryToken() @Html.ValidationSummary(true) 
  <span>@Html.EditorFor(m => m.FirstName) @Model.EnrollmentDate.ToShortDateString()</span> <input type="submit" value="Submit" />                   
}
</div>

初步观点是：

提交后：

提交后正文的源代码：

<div id="body">

            <section class="content-wrapper main-content clear-fix">

<script src="/Scripts/jquery-1.8.2.js"></script>
<script src="/Scripts/jquery.unobtrusive-ajax.js"></script>
<script type="text/javascript">  var onSuccess = function (result) { if (result.url) { window.location.href = result.url; } }
  // when server returns JSON object containing an url property redirect the browser </script>
<h1>Student</h1>
<div id="IDXForm">
<form action="/" data-ajax="true" data-ajax-method="Post" data-ajax-mode="replace" data-ajax-success="onSuccess" data-ajax-update="#IDXForm" id="form0" method="post"><input name="__RequestVerificationToken" type="hidden" value="vkCszJu-fKT6zUr5ys2StOTPF6a9pZdj5k1MyaAZKo8MPweS53dUuni0C9B17NjL_GVydHa7-jI1H0F9HrYEdKxeCWq9mCeER3ebaZYLxIs1" /><span><input class="text-box single-line" id="FirstName" name="FirstName" type="text" value="Carson" /> 9/1/2005</span> <input type="submit" value="Submit" />                                                                                                     
</form></div>

任何人都可以看到我的代码有什么问题吗？

谢谢.