web使用rem自适应

 1 (function(doc, win) {
 2     var docEl = doc.documentElement,
 3         resizeEvt = ‘orientationchange‘ in window ? ‘orientationchange‘ : ‘resize‘,
 4         recalc = function() {
 5             var clientWidth = docEl.clientWidth;
 6             if (!clientWidth) return;
 7             // if (clientWidth >= 750) {
 8             //     docEl.style.fontSize = ‘100px‘;
 9             // } else {
10             docEl.style.fontSize = 20 * (clientWidth / 375) + ‘px‘;
11             // }
12         };
13 
14     if (!doc.addEventListener) return;
15     win.addEventListener(resizeEvt, recalc, false);
16     doc.addEventListener(‘DOMContentLoaded‘, recalc, false);
17 })(document, window);