please elaborate the use of 'clearfix' property !

Answer 1

A clearfix is a way for an element to automatically clear its child elements, so that you don't need to add additional markup. It's generally used in float layouts where elements are floated to be stacked horizontally.

The clearfix is a way to combat the zero-height container problem for floated elements

A clearfix is performed as follows:

.clearfix:after {
content: " "; /* Older browser do not support empty content */
visibility: hidden;
display: block;
height: 0;
clear: both;
}

Answer 2

Normally you would need to do something as follows:
<div>
<div style="float: left;">Sidebar</div>
<div style="clear: both;"></div> <!-- Clear the float -->
</div>
With clearfix, you only need to
<div class="clearfix">
<div style="float: left;" class="clearfix">Sidebar</div>
<!-- No Clearing div! -->
</div>

Answer 3

For new browsers, just set
display: flow-root
would make clearfix at the end of the container.

Answer 4

understood !