Edit in JSFiddle


              
            
          
            
              
                
<div class="wrap">
    <div class="box1">box1</div>
    <div class="box2">box2</div>   
</div>
.box1{
    height:100px;
    background:#99FF33;
    float:left;
}
.box2{
    height:100px;
    background:#FF99FF;
    float:left;
}
.wrap{
    border:solid 1px black; 
}