布局如图
flex实现
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>使用flex实现，侧栏固定宽度</title>
<style>
html, body, p {
padding: 0;
margin: 0;
}
section {
display: flex;
flex: 1;
flex-wrap: wrap;
}
section div {
flex: 1;
}
.header {
height: 70px;
background: red;
}
.footer {
height: 70px;
background: #808080;
}
.sidebar {
flex: 0 0 200px; /* 固定宽度，不需要缩放 */
height: 300px;
background: green;
}
.ads {
height: 200px;
background: #DDDDDD;
}
.conve {
flex: 0 0 100px; /* 固定宽度，不需要缩放 */
height: 300px;
background: yellow;
}
.main {
height: 100px;
color: #fff;
background: black;
}
.inner-box {
display: flex;
flex: 1;
flex-wrap: wrap;
}
.inner-box .nav {
flex: 1 0 100%;
height: 100px;
background: orange;
}
.inner-box .conve {
flex: 0 0 200px;
}
.inner-box .ads {
flex-grow: 1;
}
.inner-main {
display: flex;
flex: 1;
flex-direction: column;
}
.inner-main .main {
margin-left: -200px; /* 200px是sidebar的width */
}
</style>
</head>
<body>
<div class="header"><p>header</p></div>
<section>
<div class="sidebar">
<p>sidebar</p>
<p>固定宽度，200px</p>
<p>nav，ads, conve, main都属于子容器inner-box</p>
</div>
<!-- inner-box整个容器会自适应sidebar之外的空间 -->
<div class="inner-box">
<div class="nav">
<p>nav</p>
<p>父容器为inner-box, 自适应宽度,占满inner-box的一行</p>
<p>ads, main属于孙容器inner-main</p>
</div>
<!-- 由于为父容器inner-box设置了换行，nav占了一行，所以inner-main会换行 -->
<!-- 占满除去conve固定宽度的其余空间 -->
<div class="inner-main">
<div class="ads">
<p>ads</p>
<p>自适应宽度，在容器inner-main中，设置了垂直布局，所以ads会占满这一行</p>
</div>
<div class="main">
<p>main</p>
<p>main在容器inner-main中，所以填满也只有inner-main的宽度(也就是和ads一样宽)，设置其margin-left为
sidebar的宽度的负值，自身自适应宽度，就可以填补sidebar下面的空白区，达到效果</p>
</div>
</div>
<!-- 和inner-main在同一行 -->
<div class="conve">
<p>conve</p>
<p>固定宽度，200px</p>
</div>
</div>
</section>
<div class="footer"><p>footer</p></div>
</body>
</html>
浮动实现
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>浮动布局，侧栏固定宽度</title>
<style>
html, body, p {
margin: 0;
padding: 0;
}
.header {
height: 50px;
width: 100%;
background: red;
}
.wraper {
overflow: hidden;
}
.sidebar {
float: left;
width: 200px;
height: 300px;
background: green;
}
.nav {
overflow: hidden;
height: 100px;
background: #F6A428;
}
.inner-box .ads {
overflow: hidden;
height: 200px;
background: #DDDDDD;
}
.inner-box .conve {
float: right;
width: 200px;
height: 400px;
background: yellow;
}
.main {
overflow: hidden;
height: 200px;
color: #fff;
background: black;
}
.footer {
float: left;
clear: both;
height: 100px;
width: 100%;
background: #808080;
}
</style>
</head>
<body>
<div class="container">
<div class="header"><p>header</p></div>
<div class="wraper">
<div class="sidebar">
<p>sidebar</p>
<p>左浮动，固定宽度200px</p>
</div>
<div class="nav">
<p>nav</p>
<p>overflow:hidden; 实现BFC，不会被浮动的sidebar遮挡，紧随其后</p>
</div>
<div class="inner-box">
<div class="conve">
<p>conve</p>
<p>右浮动，固定宽度200px</p>
</div>
<div class="ads">
<p>ads</p>
<p>ads，conve，main放在一个div里面</p>
<p>ads设置overflow:hidden;实现BFC，自适应剩下的宽度，不会被左浮动的sidebar和右浮动的conve遮挡</p>
</div>
<div class="main">
<p>main</p>
<p>overflow:hidden;紧随右浮动的conve，自适应剩下的宽度</p>
</div>
</div>
</div>
<div class="footer"><p>footer</p></div>
</div>
</body>
</html>
