.Include("~/Scripts/JQuery/jquery-1.11.2.min.js")
.Include("~/Scripts/JQuery/jquery.unobtrusive-ajax.js")
.Include("~/Scripts/JQuery/jquery.validate.min.js")
.Include("~/Scripts/JQuery/jquery.validate.unobtrusive.js")

<add key="ClientValidationEnabled" value="true" />
<add key="UnobtrusiveJavaScriptEnabled" value="true" />

@using (Ajax.BeginForm("Cadastrar", "Produto", FormMethod.Post, new AjaxOptions
                {
                    OnBegin = "onBegin",
                    OnSuccess = "onSuccess",
                    UpdateTargetId = "result"
                },
        new
        {
            enctype = "multipart/form-data",
            data_ajax = "false"
        }))

var onBegin = function() {
    $.LoadingOverlay("show");
}