var fun = function (doc, win) { var docEl = doc.documentElement, resizeEvt = 'orientationchange' in window ? 'orientationchange' : 'resize', recalc = function () { var clientWidth = docEl.clientWidth; if (!clientWidth) return; //这里是假设在640px宽度设计稿的情况下,1rem = 20px; //可以根据实际需要修改 docEl.style.fontSize = 20 * (clientWidth / 640) + 'px'; }; if (!doc.addEventListener) return; win.addEventListener(resizeEvt, recalc, false); doc.addEventListener('DOMContentLoaded', recalc, false);}fun(document, window);