<div style="clear:both;"></div>

.clearfix:after{
  content:"";
  display:block;
  height:0;
  clear:both;
  visibility:hidden;
}

<div class="parent clearfix">
   <div class="left">left</div>
   <div class="right">right</div>
 </div>

.clearfix{zoom:1}  
.clearfix:after{
  content:"";
  display:block;
  height:0;
  clear:both;
  visibility:hidden;
}
.parent{
  background-color:red;
  width:120px;
}
.left{
  float:left;
  background-color:pink;
  height:60px;
}
.right{
  float:right;
  background-color:#abcdef;
}