New Post: FluentValidation not working on form submit when JavaScrip is disabled

publicclass UserViewModel {
    public String Email { get; set; }
    public String PhoneNumber { get; set; }
    public String FullName { get; set; }
    public String CompanyName { get; set; }
}

publicclass UserViewModelValidation: AbstractValidator<UserViewModel> {
    public UserViewModelValidation() {
        RuleFor(x => x.Email).NotNull().WithLocalizedMessage(() => ValidationResources.EmailRequired);
        RuleFor(x => x.Email).EmailAddress().WithLocalizedMessage(() => ValidationResources.EmailValid);
        RuleFor(x => x.PhoneNumber).NotNull().WithLocalizedMessage(() => ValidationResources.PhoneNumberRequired);
        RuleFor(x => x.FullName).NotNull().WithLocalizedMessage(() => ValidationResources.FullNameRequired);
        RuleFor(x => x.CompanyName).NotNull().WithLocalizedMessage(() => ValidationResources.CompanyNameRequired);
    }
}

FluentValidationModelValidatorProvider.Configure();

[HttpPost]
public ActionResult UpdateUser(UserViewModel vm) {
    if (!ModelState.IsValid)
        return View(vm);

    var service = DiConfig.Resolve<IUserService>();
    service.Update(vm);
    return RedirectToAction("Index");
}

<formaction="@Url.Action("UpdateUser", "User")">
    @Html.ValidationSummary(true)
    <divclass="form-input">
        @Html.LabelFor(m => m.Email, FormResources.Email)
        @Html.TextBoxFor(m => m.Email)
        <divclass="error-message">@Html.ValidationMessageFor(m => m.Email)</div></div><divclass="form-input">
        @Html.LabelFor(m => m.PhoneNumber, FormResources.PhoneNumber)
        @Html.TextBoxFor(m => m.PhoneNumber)
        <divclass="error-message">@Html.ValidationMessageFor(m => m.PhoneNumber)</div></div><divclass="form-input">
        @Html.LabelFor(m => m.FullName, FormResources.FullName)
        @Html.TextBoxFor(m => m.FullName)
        <divclass="error-message">@Html.ValidationMessageFor(m => m.FullName)</div></div><divclass="form-input">
        @Html.LabelFor(m => m.CompanyName, FormResources.CompanyName)
        @Html.TextBoxFor(m => m.CompanyName)
        <divclass="error-message">@Html.ValidationMessageFor(m => m.CompanyName)</div></div><divclass="form-input"><inputtype="submit"value="@FormResources.UpdateButton"></div></form>