(function(doc, win) { var docEl = doc.documentElement, resizeEvt = "orientationchange" in window ? "orientationchange" : "resize", recalc = function() { var clientWidth = docEl.clientWidth; if (!clientWidth) return; docEl.style.fontSize = 100 * (clientWidth / 750) + "px"; }; if (!doc.addEventListener) return; win.addEventListener(resizeEvt, recalc, false); doc.addEventListener("DOMContentLoaded", recalc, false); })(document, window);