移动端手机rem适配js代码

(function (doc, win) {
    var docEle = doc.documentElement,
        resizeEvt = 'orientationchange' in window ? 'orientationchange' : 'resize',
        recalc = function () {
            var clientWidth = docEle.clientWidth;
            if (!clientWidth) return;
            if(clientWidth>=750){
                docEle.style.fontSize = '50px';
            }else{
                docEle.style.fontSize = 20 * (clientWidth / 375) + 'px';//这里是1rem=20px
            }
        };
    if (!doc.addEventListener) return;
    win.addEventListener(resizeEvt, recalc, false);
    doc.addEventListener('DOMContentLoaded', recalc, false);
})(document, window);