Vertically align an div inside a div

SO #18516317 http://stackoverflow.com/questions/18516317/vertically-align-an-image-inside-a-div-with-responsive-height

by Roberto Apasajja

HTML

<div class="parentbox">
    <div class="childbox">
        I shall be in the middle of parentbox regardless of its size!
    </div>
</div>

CSS

.parentbox {
    width:500px;
    height:400px;
    border-style:solid;
}

.uabb-blog-post-inner-wrap:before {      /* create a full-height inline block pseudo-element */
    content: ' ';
    display: inline-block;
    vertical-align: middle; /* vertical alignment of the inline element */
    height: 100%;
}

.uabb-blog-post-content {
    display: inline-block;
}