Disable Submit button on ASP.NET MVC

Question

I have an ASP.NET MVC application, which does the next:

• Shows a form with a table in there, and some fields per row to be filled
• Validates the input in the fields via server validation
• A submit button, which when user clicks on it, process the request in the server (long time process, > 5 seconds)

Having such scenario, I've implemented:

1. Razor view with the proper logic to show the form
2. Controller to receive the action addressed by the Submit button
3. Model with the properties to exchange between controller and view

I would like to fulfill the next requirement:

-When Submit button is clicked

• EITHER disable it (till success or error)
• OR show a modal progress bar (till success or error)

All these, in order to avoid the user to click again in the submit button while the server is processing the request.

If I disable the button via Javascript , the controller post action is never called, so disabling it via Javascript is not a solution

Implementing the PRG pattern does help, as the button is still enabled.

Controller:

    public ActionResult Index()
    {
        var viewModel = Initialize();
        return View(viewModel);
    }

    [HttpPost]
    public ActionResult HandleErrors(List<elements> entries)
    {
        var viewModel = new MyViewModel();

            entries.ForEach(entry =>
            {
                //Add validation errors to UI via ModelState when applies
                //validate CorrectionInfo
                if (string.IsNullOrEmpty(entry.Property1))
                {
                    ModelState.AddModelError("Property1" + entry.Key, "Correction info is required");
                }

                //more validations ......
            });

        if (ModelState.IsValid)
        {
            //save changes in DB
            if (DataBaseManager.SaveChanges(entries))
            {
                return RedirectToAction("Index", "MyController");
            }
            else // there were errors saving entries into the DB
            {
                viewmodel.Error = true;
                return View("Index", viewModel);
            }

        }
        else //ModelState is not valid
        {
            viewModel.ValidationErrors = true;
            return View("Index", viewModel);
        }

    }

View:

using (Html.BeginForm("HandleErrors", "MyController", FormMethod.Post))
    {
        <table id="filesTable" class="table table-striped table-bordered">
            <thead>
            <tr>
                <td>Column 1</td>
                <td>Column 2</td>
                ...
                ...
            </tr>
            </thead>
            <tbody>
            @for (int i = 0; i < Model.Entries.Count; i++)
            {
                <tr>
                    <td>
                        @Model.Entries[i].Property1
                    </td>
                    <td>
                        @Model.Entries[i].Property2
                    </td>
                    ...
                    ...
                </tr>
            }
            </tbody>
            <tfoot>
            <tr>
                <td colspan="4">
                    <input type="submit" value="Submit" />
                </td>
            </tr>
            </tfoot>
        </table>

    }

Thank you!!