How to show an overlay div when hover on a div with jQuery?

Question

I want to show an overlay div sitting on top of the hovered div similar to this effect on IBM website: http://www.ibm.com/us/en/

Please look at the 3 boxes near the footer. Hover on the box "Let's build a smarter planet" to view the effect.

Answer 1

I've created a working example. Basically you need to create 3 divs with a visible and the invisible containers, add hover event handler and toggle the tooltip's visibility in that handler.

HTML:

<div class="parents">
    <div class="box type-1">box 1</div>
    <div class="tooltip type-1">tooltip 1</div>
</div>

<div class="parents">
    <div class="box type-2">box 2</div>
    <div class="tooltip type-2">tooltip 2</div>
</div>

<div class="parents">
    <div class="box type-3">box 3</div>
    <div class="tooltip type-3">tooltip 3</div>
</div>

CSS:

.parents
{
    float: left;
    margin: 5px;
}

.box,
.tooltip
{
    width: 80px;
    height: 30px;
    line-height: 30px;

    background-color: #666;
    color: #fff;
    border: 1px solid #222;
    text-align: center;
}

.tooltip
{
    display: none;
    position: absolute;
    top: 50px;
}

jQuery code:

$(document).ready
(
    function ()
    {
        // add hover event handler
        $('.box').hover
        (
            function ()
            {
                // find the triggering box parent, and it's tooltip child
                $(this).parent().children('.tooltip').animate
                (
                    {
                        opacity: "toggle",      // toggle opacity
                    }
                );
            }
        );
    }
);

Answer 2

IBM is using Dojo's .expand method. You can do the same functionality in jQuery using the expand plugin.