rem.html

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>rem适配方案</title>
    <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=no, maximum-scale=1">
    <style>
      .one {
        width: 1rem;
        height: 1rem;
        background: #ff9999;
        border-bottom: 0.01rem solid #333;
      }
    </style>
  </head>
  <body>
    <div class="one">

    </div>
  </body>
  <script type="text/javascript">
    (function(win){
      var doc = window.document; // 整个文档
      var docE1 = doc.documentElement; //根节点 html
      var tid;

      function refreshRem() {
        var width = win.innerwidth || docE1.clientWidth;  // 边界矩形
        console.log(width);
        if (width > 540) { // 最大宽度
          width = 540;
        }
        var rem = width / 3.75;
        docE1.style.fontSize = rem + 'px';
      }

      win.addEventListener('resize', function(){
        clearTimeout(tid);
        tid = setTimeout(refreshRem,300)
      },false)

      win.addEventListener('pageshow',function (e) {
        if (e.persisted) {
          clearTimeout(tid);
          tid = setTimeout('refreshRem', 300)
        }
      },false)

      refreshRem();

    })(window)
  </script>
</html>