<div class="wrap clear" > <h2>5) 父元素设置display:table </h2> <div class="box1 left">box1 float:left;</div> <div class="box2 left">box2 float:left;</div> </div> <div class="footer">.footer</div>
.clear{ display:table; } .box1{ height:100px; background:#99FF33; } .box2{ height:100px; background:#FF99FF; } .left{ float:left; } .right{ float:right; } .wrap{ border:solid 1px black; } .footer{ background:lightblue; }