概念
例题：求ie标准盒模型和w3c盒模型红色区域的宽度和高度
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width">
<title>test</title>
<style>
.box{
width:100px;
height:100px;
background:red;
padding:10px;
border:20px blue solid;
margin:10px;
}
#border-box{
box-sizing: border-box;
}
#content-box{
box-sizing: content-box;
}
</style>
</head>
<body>
<div>
<div class='box' id="border-box"></div>
<div class='box' id="content-box"></div>
</div>
</body>
</html>运行：
