<!doctype html>
<html>
<head>
<meta name="renderer" content="webkit">
<meta http-equiv="X-UA-Compatible" content="IE=Edge,chrome=1">
<meta charset="utf-8">
<meta name="viewport" content="width=device-width,minimum-scale=1,maximum-scale=1,user-scalable=no">
<meta name="format-detection" content="telephone=no">
<meta name="apple-mobile-web-app-capable" content="yes">
<script type="text/javascript" src="http://wap.tszyzx.com/js/jquery-1.10.1.min.js"></script>
<script>
(function (doc, win) {
var docEl = doc.documentElement,
resizeEvt = 'orientationchange' in window ? 'orientationchange' : 'resize',
recalc = function () {
var clientWidth = docEl.clientWidth;
if (!clientWidth) return;
if(clientWidth>=640){
docEl.style.fontSize = '100px';
}else{
docEl.style.fontSize = 100 * (clientWidth / 640) + 'px';
}
};
if (!doc.addEventListener) return;
win.addEventListener(resizeEvt, recalc, false);
doc.addEventListener('DOMContentLoaded', recalc, false);
})(document, window);
</script>
<title>无标题文档</title>
<style>
body{ margin:0px; padding:0px;}
</style>
</head>
<body>
<div style="background:url(2-1.jpg) no-repeat; background-size:100%; height:3.65rem; border:solid 1px #f90; font-size:0.5rem">sadf</div>
</body>
</html>
关键部分，引入js代码部分设置font-size可以按照比例变化。
默认font-size:16px;
通过js根据实际尺寸调整font-size
根据1rem=100px，但是像素是变化的，这里有css的像素和实际物理像素的区别的问题？
docEl.style.fontSize = 100 * (clientWidth / 640) + 'px';