CSS布局 -- 左右定宽，中间自适应

左右定宽，中间自适应

有几种方法可以实现

改变窗口大小看看？

方案一：

左右设置绝对定位，定宽，中间设置margin-left margin-right

查看 demo

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
<title>左右定宽，中间自适应(1)</title>
<style type="text/css">
    *{margin: 0;padding: 0;}
    .left{
        position: absolute;
        top: 0;
        left: 0;
        width: 200px;
        border: 1px solid #333;
        background: #aaa;
    }
    .right{
        position: absolute;
        top: 0;
        right: 0;
        width: 220px;
        background: #aaa;
    }
    .middle{ 
        margin-left: 200px;
        margin-right: 220px;
        border: 1px solid #333;
        background: #ccc;
        word-break: break-all;
    }
</style>
</head>
<body>
    <div class="left">
    <h4>left</h4>
        <p>oooooooooooooo
        0000000000000000
        00000000000000000
        ooooooooooooooo
        ooooooooooooooo
        000000000000000</p>
    </div>
    <div class="middle">
        <h4>middle</h4>
        <p>HHHHHHHHHHHHHHHHHHHHHH
        hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh
        HHHHHHHHHHHHHHHHHHHHHH
        hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh
        </p>
    </div>
    <div class="right">
    <h4>right</h4>
        <p>BBBBBBBBBBBBBB
        888888888888888888
        BBBBBBBBBBBBBBBBBB
        88888888888888888888</p>
    </div>
</body>
</html>

方案二：

采用负边距处理。左中右都float：left;

中间的div里边再设置一个div ,外层div占满 width:100%; 内层div使用margin-left 和margin-right

左边加上负边距 margin-left:-100% 拉回最左端

右边加上负边距 margin-left:-220px (即为右边的宽度)拉回最右端

查看 demo

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
<title>左右定宽，中间自适应(2)</title>
<style type="text/css">
    *{margin: 0;padding: 0;}
    .left{
        float: left;
        margin-left: -100%;
        width: 200px;
        border: 1px solid #333;
        background: #aaa;
    }
    .right{
        float: left;
        margin-left: -220px;
        width: 220px;
        background: #aaa;
    }
    .middle{ 
        float: left;
        width: 100%;
    }
    .middle-inner{ 
        margin-left: 200px;
        margin-right: 220px;
        border: 1px solid #333;
        background: #ccc;
        word-break: break-all;
    }
</style>
</head>
<body>
    <div class="middle">
    <div class="middle-inner">
        <h4>middle</h4>
        <p>HHHHHHHHHHHHHHHHHHHHHH
        hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh
        HHHHHHHHHHHHHHHHHHHHHH
        hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh
        </p>
        </div>
    </div> 
    <div class="left">
    <h4>left</h4>
        <p>oooooooooooooo
        0000000000000000
        00000000000000000
        ooooooooooooooo
        ooooooooooooooo
        000000000000000</p>
    </div>

      <div class="right">
    <h4>right</h4>
        <p>BBBBBBBBBBBBBB
        888888888888888888
        BBBBBBBBBBBBBBBBBB
        88888888888888888888</p>
    </div>
</body>
</html>

方案三：

左边使用float:left 右边用float:right，html代码中的中间部分要放后边

查看 demo

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
<title>左右定宽，中间自适应(3)</title>
<style type="text/css">
    *{margin: 0;padding: 0;}
    .left{
        float: left;
        width: 200px;
        border: 1px solid #333;
        background: #aaa;
    }
    .right{
        float: right;
        width: 220px;
        background: #aaa;
    }
    .middle{ 
        margin-left: 200px;
        margin-right: 220px;
        border: 1px solid #333;
        background: #ccc;
        word-break: break-all;
    }
</style>
</head>
<body>
    <div class="left">
    <h4>left</h4>
        <p>oooooooooooooo
        0000000000000000
        00000000000000000
        ooooooooooooooo
        ooooooooooooooo
        000000000000000</p>
    </div>
    <div class="right">
    <h4>right</h4>
        <p>BBBBBBBBBBBBBB
        888888888888888888
        BBBBBBBBBBBBBBBBBB
        88888888888888888888</p>
    </div>
        <div class="middle">
        <h4>middle</h4>
        <p>HHHHHHHHHHHHHHHHHHHHHH
        hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh
        HHHHHHHHHHHHHHHHHHHHHH
        hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh
        </p>
    </div>
</body>
</html>