双飞翼布局

描述：两边内容不变，中间内容变化
代码：
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title></title>
    <style>
        *{
            margin: 0px;
            padding:0px;
        }
        .content{
            width: 100%;
            height: 300px;
            background-color: grey;
        }
        .center{
            width: 100%;
            height: 300px;
            background-color: red;
            float: left;
        }
        .child{
            height: 100%;
            margin-left: 100px;
            margin-right: 200px;
        }
        .left{
            width: 100px;
            height: 100%;
            background-color: blue;
            float: left;
            margin-left: -100%;
        }
        .right{
            width: 200px;
            height: 100%;
            background-color: yellow;
            float: left;
            margin-left: -200px;
        }
    </style>
</head>
<body>
<div class="content">
<div class="center">
    <div class="child">中间内容</div>
</div>
<div class="left">左边内容</div>
<div class="right">右边内容</div>
</div>
</body>
</html>