Vertically center div with Javascript (variable height)

Question

I'm trying to vertically center a div with Javascript. Because the text is going to be changing, I cannot use a fixed height.

I'd like to do this without Jquery.

#box2 {

    width: 100%;
    height: 100%;
    position:relative;
    background-color: orange;

}
            #informationBox {

            padding: 0.5em;
            background-color: #fff;
            border-radius: 12pt;
            border: solid black 3pt;
            max-width: 683px;
            margin: 0 auto;
            text-align: center;
        }

Javascript:

var container = document.getElementById("#box2");
var inner = document.getElementById("#informationBox");
var inHeight = inner.offsetHeight;

container.style.height=(window.innerHeight);
container.style.width=window.innerWidth;

var conHeight=container.offsetHeight;

inner.style.marginTop=((conHeight-inHeight)/2);

Any help would be great :)

http://jsfiddle.net/tmyie/EttZQ/

Answer 1

You pretty much have it, you just need to change a couple things. First, getElementById takes just an id-string, not a selector. Secondly, you need to add 'px' to your style declration.

var container = document.getElementById("box2");
var inner = document.getElementById("informationBox");
var inHeight = inner.offsetHeight;
container.style.height = window.innerHeight;
container.style.width = window.innerWidth;
var conHeight = container.offsetHeight;

inner.style.marginTop = ((conHeight-inHeight)/2)+'px';

Here's an updated fiddle: http://jsfiddle.net/EttZQ/1/