EPiServer.Forms show loading icon

When submission process takes a long time to complete, a loading icon should be shown just to let users know something is happening. It is easily done with EPiServer.Forms

1. Create FormStyle.css file to write cutom style for form and put it under ~/ClientResources/Styles folder. 

.modal {
    display: none;
    position: fixed;
    z-index: 9999;
    top: 0;
    left: 0;
    height: 100%;
    width: 100%;
    background: rgba( 255, 255, 255, .8 ) url('http://i.stack.imgur.com/FhHRx.gif') 50% 50% no-repeat;
    margin: 0;
}

.loading .modal {
    overflow: hidden;
}

.loading .modal {
    display: block;
}

2. Create a file name FormScript.js and put it under ~/ClientResources/Scripts folder. We will hook into Form's events to show/hide loading icon

if (typeof $$epiforms !== 'undefined') {

    var $body = $("body");
    var $loadingDiv = $('<div class="modal"></div>');
    $body.append($loadingDiv);
    epi.EPiServer.Forms.AsyncSubmit = true;

    $$epiforms(document).ready(function myfunction() {
        // listen to event when form is about submitting
        $$epiforms(".EPiServerForms").on("formsStartSubmitting", function (data) {
            //var $formContainer = $('#' + data.workingFormInfo.Id);
            //$formContainer.addClass("loading");
            $body.addClass('loading');
        });

        // listen to event when form is successfully submitted
        $$epiforms(".EPiServerForms").on("formsSubmitted", function (data) {
            $body.removeClass('loading');
        });

        // formsSubmittedError
        $$epiforms(".EPiServerForms").on("formsSubmittedError", function (data) {
            $body.removeClass('loading');
        });
    });
}

3. Register external client resources that we just created above to EPiServer.Forms.

using System;
using System.Collections.Generic;
using EPiServer.Forms.Implementation;
using EPiServer.ServiceLocation;

/// <summary>
/// Register client resources to EPiServer.Forms
/// </summary>
[ServiceConfiguration(ServiceType = typeof(IViewModeExternalResources))]
public class ViewModeExternalResources : IViewModeExternalResources
{
    public virtual IEnumerable<Tuple<string, string>> Resources
    {
        get
        {
            var arrRes = new List<Tuple<string, string>>();
            arrRes.Add(new Tuple<string, string>("script", "/ClientResources/Scripts/FormScript.js"));
            arrRes.Add(new Tuple<string, string>("css", "/ClientResources/Styles/FormStyle.css"));

            return arrRes;
        }
    }
}

When form is submitting, the page will look like this

Note: If submission process does not take long we might not see the loading icon. In this case, debug on dev tools to see the result.