(function(doc, win, designwidth, maxwidth) {
    var docel = doc.documentelement,
        resizeevt = 'orientationchange' in window ? 'orientationchange' : 'resize',
        recalc = function() {
            var clientwidth = docel.clientwidth;
            if (!clientwidth) return;
            if (clientwidth > maxwidth) clientwidth = maxwidth;
            docel.style.fontsize = 100 * (clientwidth / designwidth) + 'px';
        };


    if (!doc.addeventlistener) return;
    win.addeventlistener(resizeevt, recalc, false);
    doc.addeventlistener('domcontentloaded', recalc, false);
})(document, window, 768, 768);