How can I get the browser's scrollbar sizes?

Question

How can I determine the height of a horizontal scrollbar, or the width of a vertical one, in JavaScript?

Answer 1

detectScrollbarWidthHeight: function() {
    var div = document.createElement("div");
    div.style.overflow = "scroll";
    div.style.visibility = "hidden";
    div.style.position = 'absolute';
    div.style.width = '100px';
    div.style.height = '100px';
    document.body.appendChild(div);

    return {
        width: div.offsetWidth - div.clientWidth,
        height: div.offsetHeight - div.clientHeight
    };
},

Tested in Chrome, FF, IE8, IE11.