List viewport for mobile testing in desktop browser

/*
This piece of code creates a div (in upper left corner) that shows the viewport of current webpage. The viewport size will change when the browser window gets resized. You can insert it anywhere in your code after jQuery has been included.
Note: requires jQuery
*/
$(function(){
    function createDiv() {
        var div = $('<div />');
        div.attr({style: 'position: fixed; top: 0; left: 0; border: 1px #aaa solid; background-color: #fff; padding: 2px 4px; color: #444; font-size: 12px;', id: 'viewport'});
        $('body').append(div);
    }
    var _t;
    function windowResized() {
        clearTimeout(_t);
        _t = setTimeout(function() {
            var w = Math.max(document.documentElement.clientWidth, window.innerWidth || 0);
            var h = Math.max(document.documentElement.clientHeight, window.innerHeight || 0);
            $('#viewport').text('width: '+w+', height: '+h);
        }, 50);
    }

    createDiv();
    $(window).resize(windowResized);
    $(window).trigger('resize');
});