Error styling in js

Hello everyone, guys

I've been having some trouble with styling an element in my page. Can any of u see the problem?

HTML Code:

<html> <head> <script type="text/javascript"> function Window() { this._getY = function() { return(window.innerHeight); } this._getX = function() { return(window.innerWidth); } this._load = function() { var w = document.getElementById("window"); w.style.width = this._getX(); w.style.height = this._getY(); } } var WINDOW = new Window(); WINDOW._load(); </script> <style type="text/css"> #window { display: block; position: absolute; top: 0px; left: 0px; background-color:red; } </style> </head> <body> <div id="window"> Content </div> </body> </html>

I have tryed to alert the methods _getX() and _getY(), and both functions are working pretty. I think the problem it's on the styling thing, or getting the element on the page.

Maybe there's a simple error that I'm not seeing, i've spent too much time using Jquery, so probably I got too confortable on that.

Sorry for my bad english, it's not my native language.
Thank you all

You should create your object after all assets will be downloaded.
It is working code:

Code:

window.onload = function(){ var WINDOW = new Window(); WINDOW._load(); }

Thanks, kromol