https://mengchenghui.com/app/responsive.js

1(function (doc, win) {
2    // 分辨率Resolution适配
3    var docEl = doc.documentElement,
4        resizeEvt = 'orientationchange' in window ? 'orientationchange' : 'resize',
5        recalc = function () {
6            var clientWidth = docEl.clientWidth;
7            if (!clientWidth) return;
8            docEl.style.fontSize = 50 * (clientWidth / 375) + 'px';
9        };
10
11    // Abort if browser does not support addEventListener
12    if (!doc.addEventListener) return;
13    win.addEventListener(resizeEvt, recalc, false);
14    doc.addEventListener('DOMContentLoaded', recalc, false);
15
16    // 一物理像素在不同屏幕的显示效果不一样。要根据devicePixelRatio来修改meta标签的scale,要注释上面的meta标签
17    (function(){
18        return;
19        var dpr = scale =1;
20        var isIPhone = win.navigator.appVersion.match(/iphone/gi);
21        var devicePixelRatio = win.devicePixelRatio;
22        if (isIPhone) {
23            // iOS下，对于2和3的屏，用2倍的方案，其余的用1倍方案
24            if (devicePixelRatio >= 3 && (!dpr || dpr >= 3)) {
25                dpr = 3;
26            } else if (devicePixelRatio >= 2 && (!dpr || dpr >= 2)){
27                dpr = 2;
28            } else {
29                dpr = 1;
30            }
31        } else {
32            // 其他设备下，仍旧使用1倍的方案
33            dpr = 1;
34        }
35        scale = 1 / dpr;
36
37        //
38        var metaEl = "";
39        metaEl = doc.createElement('meta');
40        metaEl.setAttribute('name', 'viewport');
41        metaEl.setAttribute('content', 'initial-scale=' + scale + ', maximum-scale=' + scale + ', minimum-scale=' + scale + ', user-scalable=no');
42        if (docEl.firstElementChild) {
43            docEl.firstElementChild.appendChild(metaEl);
44        } else {
45            var wrap = doc.createElement('div');
46            wrap.appendChild(metaEl);
47            doc.write(wrap.innerHTML);
48        }
49    })();
50
51})(document, window);