带header和footer的双栏布局

1 <div id="header">header</div>
2 <div id="main">
3     <div id="content">content</div>
4 </div>
5 <div id="sidebar">sidebar</div>
6 <div id="footer">footer</div>

 1 #header {
 2     background-color: gray;
 3     height: 50px;
 4 }
 5 #main {
 6     width: 100%;
 7     float: left;
 8 }
 9 #content {
10     margin-right: 400px;
11     
12     background-color: red;
13     height: 300px;
14 }
15 #sidebar {
16     width: 400px;
17     float: left;
18     margin-left: -400px;
19     clear: right;
20     
21     background-color: green;
22     height: 100px;
23 }
24 #footer {
25     clear: both;
26 
27     background-color: gray;
28     height: 50px;
29 }