Detect and show window size in upper left of page.
(function () {
// I know chrome does this but I would like it to stay around.
// update, chrome does not do this any more.
var scaler,
scaleWrapper = ['<div id="scaleShow"',
'style="position:fixed;background:#fff;top:0;left:0;padding:5px;opacity:0.6;">',
window.innerWidth + 'px x ' + window.innerHeight + 'px - ' + window.devicePixelRatio,
'</div>'].join(' ');
document.body.insertAdjacentHTML('beforeend', scaleWrapper);
scaler = document.getElementById('scaleShow');
window.addEventListener('resize', function () {
scaler.textContent = window.innerWidth + 'px x ' + window.innerHeight + 'px';
});
}());