目录：

内容：

//设置左右浮动
.left{
    float:left;
}
.right{
    float:right;
}
/*必须设置不同浮动*/
//创建div
<div>
<dic class="left">左边</div>
<div class="right">右边</div>
</div>

//设置浮动
.left{
    width:50%;
    height:200px;
    background:pink;
    float:left;
}
.right{
    width:50%;
   height:200px;
   background:deepskyblue;
   float:right;
}
.center{
    width:100%;
    height:200px;
    background:orange;
//在被影响的标签里添加clear:both
    /* clear:both; */
}
.clear{
    clear:both;
}
//创建div
<div class="box">
    <div class="left">左边</div>
    <div class="right">右边</div>
    <div class="clear"></div>
    <div class="center"></div>
</div>

//使用::after伪对象
.box::after{
    content:'';
    width:0;
    height:0;
    display:block;
    clear:both;
    visibility: hidden;
    overflow: hidden;
    zoom:1;
            } 
//设置浮动
.left{
    width:50%;
    height:200px;
    background:pink;
    float:left;
}
.right{
    width:50%;
   height:200px;
   background:deepskyblue;
   float:right;
}
.center{
    width:100%;
    height:200px;
    background:orange;
}
//创建div
<div class="box">
    <div class="left">左边</div>
    <div class="right">右边</div>
</div>
<div class="center"></div>

//设置浮动
.left{
    width:50%;
    height:200px;
    background:pink;
    float:left;
}
.right{
    width:50%;
   height:200px;
   background:deepskyblue;
   float:right;
}
.center{
    width:100%;
    height:200px;
    background:orange;
//给被影响的元素添加overflow:hidden
    overflow:hidden;
}

//创建div
<div class="box">
    <div class="left">左边</div>
    <div class="right">右边</div>
    <div class="center"></div>
</div>

.one{
    width:300px;
    height:300px;
    background:red;
    overflow:hidden;
}
.two{
    width:100px;
    height:100px;
   background:deepskyblue;
   margin-top:100px;
/* float:left; */
position:absolute;
}
//设置div
<div class="one">
    <div class="two"></div>
</div>

.one{
    width:300px;
    height:300px;
    background:red;
}
.two{
    width:100px;
    height:100px;
   background:deepskyblue;
   margin-top:100px;
   float:left;
}
//设置div
<div class="one">
    <div class="two"></div>
</div>

.one{
    width:300px;
    height:300px;
    background:red;
}
.two{
    width:100px;
    height:100px;
   background:deepskyblue;
   margin-top:100px;
   position:absolute;
}
//设置div
<div class="one">
    <div class="two"></div>
</div>