移动端使用rem时候动态设置html字体大小

 

!(function(doc, win) {
    var docEle = doc.documentElement,
        evt = "onorientationchange" in window ? "orientationchange" : "resize",
        fn = function() {
            var width = docEle.clientWidth;
            width && (docEle.style.fontSize = 20 * (width / 320) + "px");
        };

    win.addEventListener(evt, fn, false);
    doc.addEventListener("DOMContentLoaded", fn, false);

}(document, window));