###代码
(function(doc, win) {
var docEl = doc.documentElement,
isIOS = navigator.userAgent.match(/\(i[^;]+;( U;)? CPU.+Mac OS X/),
dpr = isIOS ? Math.min(win.devicePixelRatio, 3) : 1,
dpr = window.top === window.self ? dpr : 1, //被iframe引用时,禁止缩放
resizeEvt = 'orientationchange' in window ? 'orientationchange' : 'resize';
docEl.dataset.dpr = dpr;
var recalc = function() {
var width = docEl.clientWidth;
if (width / dpr > 1080) {
width = 1080 * dpr;
}
docEl.dataset.width = width
docEl.dataset.percent = 100 * (width / 1080);
docEl.style.fontSize = 100 * (width / 1080) + 'px';
};
recalc()
if (!doc.addEventListener) return;
win.addEventListener(resizeEvt, recalc, false);
})(document, window);
####以上,注意出现1080 的地方,这里改成设计图的宽度即可,这段代码的好处是根元素font-size是100 计算方便,若要给页面设置宽度 1080 = 10.8rem 640 = 6.4rem 等,字号的话直接根据设计图除以100即可,注意头部
<meta name="viewport" content="width=device-width,initial-scale=1,maximum-scale=1,user-scalable=no">
####别忘了。