1 html, body {
 2 height: 100%;
 3 margin: 0;
 4 padding: 0;
 5 }
 6 #header {
 7 height: 100px;
 8 background: #ddd;
 9 position: relative;
10 z-index: 1;
11 }
12 #content-box {
13 min-height: 100%;
14 margin: -100px 0 -50px;
15 }
16 *html #content-box {
17 height: 100%;
18 }
19 #content {
20 padding: 100px 0 50px;
21 }
22 #footer {
23 height: 50px;
24 background: #ddd;
25 }
 1 <div>
 2   header (height 100pixel)
 3 div>
 4 <div>
 5   <div>
 6     <p>contentsp><p>contentsp><p>contentsp>
 7   div>
 8 div>
 9 <div>
10   footer (height 50pixel)
11 div>