Cross-browser, consistent float-containment methods

contain-floats.css

/* 
 * Containing floats in a consistent manner
 * By Jonathan Neal and Nicolas Gallagher
*/

/* 
 * New block formatting context method
 * IE 6+, Firefox 2+, Safari 4+, Opera 9+, Chrome
*/

.nbfc {
    overflow: hidden;
    /* for IE 6/7 */
    *zoom: expression(this.runtimeStyle.zoom="1", this.appendChild(document.createElement("br")).style.cssText="clear:both;font:0/0 serif");
    /* non-JS fallback */
    *zoom: 1;
}

/* 
 * Clearfix method (contemporary browsers)
 * IE 6+, Firefox 3.5+, Safari 4+, Opera 9+, Chrome
 * (needs old mobile browser testing)
*/

.cf {
    /* for IE 6/7 */
    *zoom: expression(this.runtimeStyle.zoom="1", this.appendChild(document.createElement("br")).style.cssText="clear:both;font:0/0 serif");
    /* non-JS fallback */
    *zoom: 1;
}

.cf:before,
.cf:after {
    content: "";
    display: table;
}

.cf:after {
    clear: both;
}

/* 
 * Clearfix method (increased legacy browser support)
 * IE 6+, Firefox 2+, Safari 4+, Opera 9+, Chrome
*/

.cf {
    /* for IE 6/7 */
    *zoom: expression(this.runtimeStyle.zoom="1", this.appendChild(document.createElement("br")).style.cssText="clear:both;font:0/0 serif");
    /* non-JS fallback */
    *zoom: 1;
}

.cf:before,
.cf:after {
    content: ".";
    display: block;
    height: 0;
    overflow: hidden;
    visibility: hidden; 
}

.cf:after {
    clear: both;
}

@parweb That expression is longer although it's unlikely you'd need the font part when using a div. However, by using an element like div the technique becomes more brittle because someone may choose to style div within an element receiving the clearfix class. If you were to write some CSS like

.container > div {border:5px solid red; min-height:100px;}

Then your clearing div is going to get those extra styles in IE7. This is why we are using br. It's safer and easier

thank for the precision ;)