Clearfix

.clearfix:after {
    content: " "; /* 1 */
    display: table; /* 2 */
}
.clearfix:after {
    clear: both;
}
.clearfix {
    *zoom: 1;
}

The „Clearfix” hack

.clearfix:after {
     visibility: hidden;
     display: block;
     font-size: 0;
     content: " ";
     clear: both;
     height: 0;
     }
.clearfix { display: inline-block; }
/* start commented backslash hack \*/
* html .clearfix { height: 1%; }
.clearfix { display: block; }
/* close commented backslash hack */