左边
      
    
      
       
      
    
      
       右边
      
     

#container {    width: 400px;    height: 200px;    display: table}#left, #mid, #right {    display: table-cell;    background: #ccc;    outline: 2px dashed blue}#mid {    width: 100%;    background: #f0f;    }#left,#right {    padding-left:15px;    padding-right:15px;    white-space:nowrap;}

http://jsfiddle.net/xhCXq/350/

http://stackoverflow.com/questions/5505554/set-edge-divs-to-fill-remaining-width