How to get the height of a hidden absolute div

Question

I have a div which is hidden and has absolute position and i want to get it's height so i can set it via jQuery

.parent2{
    display: block;
    position: relative;
    overflow: hidden;
    width: 100% !important;
    height: 100% !important;
}

.hidden_div{
    position: absolute;
    width: 100% !important;
    height: 100% !important;
    padding: 15px;
    top: 0;
    left: 0;
    opacity: 0;
    visibility: hidden;
    overflow: hidden;
    overflow-y: auto;
}

I have tried the following without any result:

var div_height = $(".hidden_div").height();
var div_height = $(".hidden_div").outerHeight();
var div_height = $(".hidden_div").actual("height");
//or innerHeight or outerHeight using the plugin at https://github.com/dreamerslab/jquery.actual/

EDIT:

this is the layout:

<div class="parent1">
    <div class="parent2">
        <div class="hidden_div">

        </div>
    </div>
</div>

parent1 has no css

Answer 1

You could try to fetch the height using jQuery.

alert($("div.hidden_div").css("height"));

Example: http://jsfiddle.net/YT75Z/

Answer 2

If possible, try removing position:relative; from .parent2

.parent2{
    display: block;
    overflow: hidden;
    width: 100% !important;
    height: 100% !important;
}

http://jsfiddle.net/YT75Z/2/