console 命令行工具 X clear

console

<div class="left"></div>
<div class="right"></div>

 .left {
     width: 100px;
     height: 150px;
     float: left;
     background: greenyellow;
 }
 
 .right {
     height: 200px;
     background: palevioletred;
     /* 去掉这个代码对比一下看看 */
     overflow: hidden;
     /*触发BFC*/
 }