js: Get window width and height

script.js

var w = window,
    d = document,
    e = d.documentElement,
    g = d.getElementsByTagName('body')[0],
    x = w.innerWidth || e.clientWidth || g.clientWidth,
    y = w.innerHeight|| e.clientHeight|| g.clientHeight;
alert(x + ' × ' + y);

// From http://stackoverflow.com/questions/3437786/how-to-get-web-page-size-browser-window-size-screen-size-in-a-cross-browser-wa