console 命令行工具 X clear

console

<div class="box">
    1<hr/>
    2<hr/>
    3<hr/>
    <div class="box2">隐藏区域</div>
</div>

.box{
    overflow: hidden;
    background-color: yellow;
}
.box2{
    height: 30px;
    background-color: red;
    margin-bottom: -30px;
}