xxxxxxxxxx
<div style="overflow: auto;">
<div style="float: left;">Div 1</div>
<div style="float: left;">Div 2</div>
</div>
xxxxxxxxxx
.clearfix::after {
content: " ";
display: block;
height: 0;
clear: both;
}
xxxxxxxxxx
<div>
<div style="float: left;">Div 1</div>
<div style="float: left;">Div 2</div>
<div class="spacer" style="clear: both;"></div>
</div>
xxxxxxxxxx
<div style="float: left;">
<div style="float: left;">Div 1</div>
<div style="float: left;">Div 2</div>
</div>
xxxxxxxxxx
<div style="height: 300px;">
<div style="float: left;">Div 1</div>
<div style="float: left;">Div 2</div>
</div>