css 实现的网页布局

css 实现网页布局，上中下三部分，中间为固定宽度且分为左右两部分


<!DOCTYPE html>
<html>
 <head>
  <meta charset="UTF-8">
  <title>布局</title>
  <style>
  html,body{
         margin:0;
}
.topNav{   
  border:solid 1px red;   
  background: red;  
  position: fixed;    
  width:100%;   
  height:60px; 
  line-height:60px;    
  text-align: center;    
  color:#fff;
}
.centerContext{   
  border:solid 1px blue; 
  background: #ccc;   
  position: absolute;   
  width:1366px;    
  bottom: 40px;   
  top:60px;  
  text-align: center;   
  color:#fff;    left:0;  
  right:0;   
   margin:0 auto; 
   z-index: -1;
}
.footer{   
 border:solid 1px green; 
  background: green; 
  height:40px;   
  line-height:40px;  
  position: fixed;  
  bottom: 0;   
  width:100%; 
  text-align: center;
  color:#fff;
}
.left{ 
   border:solid 1px #669ae1;
   background: #669ae1;   
   width:300px; 
   float:left;    
   height:100%;  
   margin-bottom: 40px;
   overflow: auto;   
   color:#fff;
}
.right{
  border: solid 1px #1d5464;  
  height:100%; 
  background: #1d5464;    
  color:#fff;    
  overflow: auto;   
  margin-left: 300px;
} 
 .right div{height:1000px}
  </style>
 </head>
  <body> 
   <div class="topNav">头部</div>   
   <div class="centerContext">        
        <div class="left">左边</div>       
        <div class="right">           
             <div >我是右边里面的内容我的高度是1000px</div>  
        </div>  
  </div>   
 <div class="footer">底部</div>
</body>
</html>

上中下铺满全屏

<!DOCTYPE html>
<html>
<head lang="en">  
  <meta charset="UTF-8"> 
   <title>布局</title>   
 <style>        
html,body{margin:0}     
 .topNav{        
  border:solid 1px red;         
  background: red;          
  position: fixed;          
  width:100%;          
 height:60px;          
 line-height:60px;          
 text-align: center;          
 color:#fff;      
}      
.centerContext{          
  border:solid 1px blue;          
  background: #ccc;          
 position: absolute;          
 width:100%;          
 bottom: 40px;          
 top:60px;          
 text-align: center;          
 color:#fff;          
 left:0;          
 right:0;          
 margin:0 auto;          
 z-index: -1;      
}      
.footer{         
 border:solid 1px green;          
 background: green;          
 height:40px;          
 line-height:40px;          
 position: fixed;        
  bottom: 0;          
  width:100%;          
   text-align: center;         
  color:#fff;      
}     
 .left{         
   border:solid 1px #669ae1;          
   background: #669ae1;          
   width:20%;          
   float:left;          
   height:100%;          
   margin-bottom: 40px;          
   overflow: auto;          
   color:#fff;          
   -webkit-box-sizing: border-box;          
   -moz-box-sizing: border-box;          
   box-sizing: border-box;      
}      
.right{          
   border: solid 1px #1d5464;          
   height:100%;          
   width:80%;          
   background: #1d5464;          
   color:#fff;          
   overflow: auto;          
   -webkit-box-sizing: border-box;         
   -moz-box-sizing: border-box;         
   ox-sizing: border-box;      
}        
.right div{height:1000px}    
 </style>
</head>
<body>    
  <div class="topNav">头部</div>    
   <div class="centerContext">        
       <div class="left">左边</div>        
       <div class="right">            
  <div >我是右边里面的内容我的高度是1000px</div>        
 </div>    
 </div>    
  <div class="footer">底部</div>
 </body>
</html>