How to add header to this ajax request

Question

I would like to add a header to the following request but unsure how to add it?

"Accept":"application/json; odata=verbose";

Here is my code:

function getArticleList() {
 var ajax = new XMLHttpRequest();
 ajax.open("GET", "/content/_api/web/lists/getbytitle('topsupportarticles')/items?", true);
 ajax.onload = function () {
 var list = JSON.parse(ajax.responseText).map(function (i) { return i.Title + "<p id='dt'>-" + i.KBID + "</p>"; });
 console.log(i.Title + " " + i.KBID);
 //new Awesomplete(document.querySelector("#Title_fa564e0f-0c70-4ab9-b863-0177e6ddd247_$TextField"), { list: list });
 // $(".input-loader").css("background-image", "none");
 };
 ajax.send();
 }

Answer 1

Here is link to documentation for XMLHttpRequest https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest/setRequestHeader

Is that what you are looking for?

Answer 2

You may use it like:

ajax.setRequestHeader("Accept","application/json");