Prevent onmouseout when hovering child element of the parent absolute div WITHOUT jQuery

Use onmouseleave.

Or, in jQuery, use mouseleave()

It is the exact thing you are looking for. Example:

<div class="outer" onmouseleave="yourFunction()">
    <div class="inner">
    </div>
</div>

or, in jQuery:

$(".outer").mouseleave(function(){
    //your code here
});

an example is here.