引入：页面开头处引入下面这段代码，或者放到js里，引入即可用于动态计算font-size

<script type="text/javascript">
    (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
            dpr = 1,
            scale = 1 / dpr,
            resizeEvt = 'orientationchange' in window ? 'orientationchange' : 'resize';
        docEl.dataset.dpr = dpr;
        var metaEl = doc.createElement('meta');
        metaEl.name = 'viewport';
        metaEl.content = 'initial-scale=' + scale + ',maximum-scale=' + scale + ', minimum-scale=' + scale;
        docEl.firstElementChild.appendChild(metaEl);
        var recalc = function() {
            var width = docEl.clientWidth;
            if (width / dpr > 750) {
                width = 750 * dpr;
            }
            // 乘以100，px : rem = 100 : 1
            docEl.style.fontSize = 100 * (width / 750) + 'px';
        };
        recalc()
        if (!doc.addEventListener) return;
        win.addEventListener(resizeEvt, recalc, false);
    })(document, window);
</script>

在vue中使用的方法

(function (doc, win) {
  var docEl = doc.documentElement
  var isIOS = navigator.userAgent.match(/\(i[^;]+;( U;)? CPU.+Mac OS X/)
  var dpr = isIOS ? Math.min(win.devicePixelRatio, 3) : 1
  var scale = 1 / dpr
  var resizeEvt = 'orientationchange' in window ? 'orientationchange' : 'resize'
  docEl.dataset.dpr = dpr
  var metaEl = doc.createElement('meta')
  metaEl.name = 'viewport'
  metaEl.content = 'initial-scale=' + scale + ',maximum-scale=' + scale + ', minimum-scale=' + scale
  docEl.firstElementChild.appendChild(metaEl)
  var recalc = function () {
    var width = docEl.clientWidth
    if (width / dpr > 750) {
      width = 750 * dpr
    }
    docEl.style.fontSize = 100 * (width / 750) + 'px'
  }
  recalc()
  if (!doc.addEventListener) return
  win.addEventListener(resizeEvt, recalc, false)
})(document, window)

简单粗暴的网易适配 统统除以100，单位换成rem
使用：未引入前

body {
    width: 750px;
    height: 640px;
    font-size: 20px;
}

引入后：除以100并将px换成rem

@media screen and (max-width: 750px) {
    body {
        width: 7.5rem;
        height: 6.4rem;
        font-size: 0.2rem;
 }