看法:
@{
    AjaxOptions ajax = new AjaxOptions() { HttpMethod = "POST", UpdateTargetId = "sub_id" };
    Layout = null;       
}
<div id="sub_id"></div>
@using (Ajax.BeginForm(ajax))
{
    @Html.TextBox("email");
    <input type="submit" value="подписаться" />
}
控制器:
[HttpPost]
public ContentResult LeftMenuSubscription(string email)
{
    return new ContentResult(){Content = "<script>alert('Thanks')</script>"};
}
“谢谢”警报节目。
但在 div 中sub_id设置所有 page( <title></title><div>...</div>)。
<script src="@Url.Content("~/Scripts/jquery.unobtrusive-ajax.min.js")" type="text/javascript"></script> 
- 连接的。
html:
<html>
    <head>
        <title>Главная страница</title>
        <link href="/Content/Site.css" rel="stylesheet" type="text/css">
        <script src="/Scripts/jquery-1.7.2.min.js" type="text/javascript"></script>
        <script src="/Scripts/jquery.unobtrusive-ajax.min.js" type="text/javascript"</script>
        <script src="/Scripts/jquery.validate.min.js" type="text/javascript"></script>
        <script src="/Scripts/jquery.validate.unobtrusive.min.js" type="text/javascript"></script>
        <script src="/Scripts/jQueryFixes.js" type="text/javascript"></script>
    </head>
    <body>
        ....
        <form action="/" data-ajax="true" data-ajax-method="POST" data-ajax-mode="replace" data-ajax-update="#sub_id" id="form0" method="post">
            <input id="email" name="email" type="text" value="">
            <input type="submit" value="подписаться">
        </form>
        ....
    </body>
</html>
可能是什么问题呢?