移动端自适应rem

(function () {
var resizeEvt = 'orientationchange' in window ? 'orientationchange' : 'resize';
var recalc = function () {
var clientWidth = document.body.clientWidth;
if(!clientWidth){
return;
}
document.documentElement.style.fontSize = 10 * (clientWidth/320)+ 'px';
document.documentElement.style.visibility = 'visible';
}
if(!document.documentElement.addEventListener){
return;
}
window.addEventListener(resizeEvt,recalc,false);
window.addEventListener('DOMContentLoaded',recalc,false);
})();