Plain JavaScript tooltip

Question

I am trying to make a tooltip in plain JavaScript which is shown on hover. Like the one in Stack Overflow on hover over the profile name a div is s

Answer 1

Even for $(document).ready, it’s hard to accomplish in pure JS—see here: $(document).ready equivalent without jQuery

So I’m using a simple version:

window.addEventListener("load", function () {
    var couponcodes = document.getElementsByClassName("couponcode");
    for (var i = 0; i < couponcodes.length; i++) {
        couponcodes[i].addEventListener("mouseover", function () {
            var coupontooltip = this.getElementsByClassName("coupontooltip")[0];
            coupontooltip.removeAttribute("style");
        });
        couponcodes[i].addEventListener("mouseout", function () {
            var coupontooltip = this.getElementsByClassName("coupontooltip")[0];
            coupontooltip.style.display = "none";
        });
    }
});

http://jsfiddle.net/mynetx/5qbP3/