JSFiddle - React, Tailwind, and code Playground

HTML

<button id="button">Click Me</button>

JavaScript

$('#button').click(function() {
    var inProgress = 0;

    function handleBefore() {
        inProgress++;
    };

    function handleComplete() {
        if (!--inProgress) {
            alert('All done');
        }
    };

    $.ajax({
        beforeSend: handleBefore,
        complete: function () {
            // whatever
            handleComplete();
            // whatever
        },
        data: {
            delay: 2
        },
        url: '/echo/json'
    });
    $.ajax({
        beforeSend: handleBefore,
        complete: function () {
            // whatever
            handleComplete();
            // whatever
        },
        data: {
            delay: 2
        },
        url: '/echo/json'
    });
    $.ajax({
        beforeSend: handleBefore,
        complete: function () {
            // whatever
            handleComplete();
            // whatever
        },
        data: {
            delay: 2
        },
        url: '/echo/json'
    });
});