Simulate hover using JavaScript events

Question

Is it possible to simulate hover using JavaScript Events? I tried injecting mouseover event on the target element but no luck.

For example, if there is a link that

Answer 1

Yes, you would simply add onMouseOver and onMouseOut events to the element in question

Like this:

<div class="something" onmouseover="hover(this);" onmouseout="unhover(this);">

Then make your javascript change the element's class (if you want two different CSS classes) or simply modify the element's style directly. You could do something like this.

<script>
function hover(element) {
    element.setAttribute('class', 'something hover');
}
function unhover(element) {
    element.setAttribute('class', 'something');
}
</script>

Please note that you can also use a library like jQuery to handle this even more simply.

Answer 2

The jQuery hover event is just using mouseenter and mouseleave events. Here is the source of jQuery's hover:

function (fnOver, fnOut) {
    return this.mouseenter(fnOver).mouseleave(fnOut || fnOver);
}

Answer 3

Actually, CSS hover event is more convenient than just binding these two events mouseenter and mouseleave. So it'll need a little more efforts, which are:

1.Clone the element

2.Add a listener to mouseenter event

3.Recursively redo step 1,2 and restore the cloned element on mouseleave

Here is my working draft.

function bindHoverEvent(element,listener){
    var originalElement = element.cloneNode(true);
    element.addEventListener('mouseenter',listener);
    element.addEventListener('mouseleave',function(){
        bindHoverEvent(originalElement,listener);
        this.parentNode.replaceChild(originalElement,this);
    });
}

Please note that, cloneNode does not copy event listeners, so you need to manually rebind events to the cloned element and all its children yourself.

Answer 4

It is possible to simulate hover using JavaScript events. I created a module for swapping out images on hover. You can experiment and adapt the module to fit your needs. For the example, I made the image paths and DOM selection elements generic.

// module for swapping out images on hover 
var imageSwap = (function ModuleFactory() {

    "use strict";

    var imageContainer = document.getElementById("image-container"),
        image = document.getElementsByClassName("image")[0],
        imageSource1 = 'path/to/your/image1',
        imageSource2 = 'path/to/your/image2';

    function handleImageSwap(e) {
        if (e.target.id === "image-container") {
            image.setAttribute("src", imageSource2);

            e.target.addEventListener("mouseleave", function _handler_() {
                image.setAttribute("src", imageSource1);
                e.target.removeEventListener("mouseleave", _handler_, false);
            }, false);
        }
    }

    function init() {
        imageContainer.addEventListener("mouseenter", handleImageSwap, false);
    }

    var publicAPI = {
        init: init
    };

    return publicAPI;

})();

document.addEventListener("DOMContentLoaded", imageSwap.init(), false);