JSFiddle - React, Tailwind, and code Playground

HTML

<p>After sending requests: <span id="aftersending"></span></p>
<p>After all requests complete: <span id="aftercomplete"></span></p>

JavaScript

var aftersending = document.getElementById("aftersending"),
    aftercomplete = document.getElementById("aftercomplete"),
    globalVar = 0;

function addSquadronByID() {
	return jQuery.ajax({
    	url: "/echo/json/",
        success: function (data) {
    		globalVar++;
    	}
    });
}

var d1 = addSquadronByID(3),
    d2 = addSquadronByID(5),
    d3 = addSquadronByID(6);

aftersending.innerHTML = globalVar;

jQuery.when(d1, d2, d3).then(function () {
    aftercomplete.innerHTML = globalVar;
});