<script>
var bw=document.documentElement.clientWidth/7.2+"px";
document.getElementsByTagName("html")[0].style.fontSize=bw;
</script>
100px为1rem
<script>
var bw=document.documentElement.clientWidth/7.2+"px";
document.getElementsByTagName("html")[0].style.fontSize=bw;
</script>
100px为1rem