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 has a hover selector, is it possible to "hover" over it using JavaScript Events? Basically, I want to trigger CSS hover. You can assume I can't use jQuery.

Answer 1

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 2

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 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);