手机端页面rem宽度自适应脚本

!function(win) { function resize() {  var domWidth = domEle.getBoundingClientRect().width;  if(domWidth / v > 540){   domWidth = 540 * v;  }  win.rem = domWidth / 16;  domEle.style.fontSize = win.rem + "px"; } var v, initial_scale, timeCode, dom = win.document, domEle = dom.documentElement, viewport = dom.querySelector('meta[name="viewport"]'), flexible = dom.querySelector('meta[name="flexible"]'); if (viewport) {  //viewport：<meta name="viewport"content="initial-scale=0.5, minimum-scale=0.5, maximum-scale=0.5,user-scalable=no,minimal-ui"/>  var o = viewport.getAttribute("content").match(/initial/-scale=(["']?)([/d/.]+)/1?/);  if(o){   initial_scale = parseFloat(o[2]);   v = parseInt(1 / initial_scale);  } } else {  if (flexible) {   var o = flexible.getAttribute("content").match(/initial/-dpr=(["']?)([/d/.]+)/1?/);   if(o){    v = parseFloat(o[2]);    initial_scale = parseFloat((1 / v).toFixed(2))   }  } } if (!v && !initial_scale) {  var n = (win.navigator.appVersion.match(/android/gi), win.navigator.appVersion.match(/iphone/gi));  v = win.devicePixelRatio;  v = n ? v >= 3 ? 3 : v >= 2 ? 2 : 1 : 1, initial_scale = 1 / v } //没有viewport标签的情况下 if (domEle.setAttribute("data-dpr", v), !viewport) {  if (viewport = dom.createElement("meta"), viewport.setAttribute("name", "viewport"), viewport.setAttribute("content", "initial-scale=" + initial_scale + ", maximum-scale=" + initial_scale + ", minimum-scale=" + initial_scale + ", user-scalable=no"), domEle.firstElementChild) {   domEle.firstElementChild.appendChild(viewport)  } else {   var m = dom.createElement("div");   m.appendChild(viewport), dom.write(m.innerHTML)  } } win.dpr = v; win.addEventListener("resize", function() {  clearTimeout(timeCode), timeCode = setTimeout(resize, 300) }, false); win.addEventListener("pageshow", function(b) {  b.persisted && (clearTimeout(timeCode), timeCode = setTimeout(resize, 300)) }, false); /* 个人觉得没必要完成后就把body的字体设置为12 "complete" === dom.readyState ? dom.body.style.fontSize = 12 * v + "px" : dom.addEventListener("DOMContentLoaded", function() {  //dom.body.style.fontSize = 12 * v + "px" }, false); */ resize();}(window);