实例
<!-- 1. 实例演示如何消除子元素浮动造成父元素高度折叠的影响
2. 实例演示三列布局的实现原理( 绝对定位实现, 浮动定位实现)-->
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
h3 span{
font-size: 14px;
}
.parent{
background-color: #ccc;
overflow: hidden;
}
.child{
height: 400px;
width: 400px;
background-color: black;
float: left;
}
.container{
width: 1000px;
min-height: 100px;
margin: 0 auto;
}
.header{
width: 100%;
min-height: 100px;
background-color: #ccc;
}
/* 绝对定位实现三栏式布局 */
.main{
width: 100%;
min-height: 500px;
/* background-color: #f00; */
margin: 10px auto;
position: relative;
}
.main .left{
width: 300px;
height: 500px;
background-color: blue;
position: absolute;
left: 0;
top: 0;
}
.main .cen{
width: 400px;
height: 500px;
background-color: red;
position: absolute;
left: 300px;
top: 0;
}
.main .right{
width: 300px;
height: 500px;
background-color: yellowgreen;
position: absolute;
left: 700px;
top: 0;
}
/* 浮动实现三栏式布局 */
.two_main{
width: 100%;
min-height: 500px;
margin: 10px auto;
}
.two_main .left, .two_main .right{
width: 300px;
height: 500px;
}
.two_main .left{
background-color: #ccc;
float: left;
}
.two_main .right{
background-color: #000;
float: right;
}
.two_main .cen{
width: 600px;
height: 500px;
margin-left: 300px;
background-color: yellowgreen;
}
.footer{
width: 100%;
min-height: 100px;
background-color: #0ff;
}
</style>
</head>
<body>
<h3>第一题 <span>实例演示如何消除子元素浮动造成父元素高度折叠的影响。</span></h3>
<p>推荐在父级添加 overflow:hidden 属性实现清除浮动</p>
<div class="parent">
<div class="child"></div>
</div>
<h3>第二题 <span>实例演示三列布局的实现原理( 绝对定位实现, 浮动定位实现)。</span></h3>
<p style="text-align: center;">绝对定位实现三栏式布局</p>
<div class="container">
<div class="header"></div>
<div class="main">
<div class="left"></div>
<div class="cen"></div>
<div class="right"></div>
</div>
<div class="footer"></div>
</div>
<p style="text-align: center;">浮动实现三栏式布局</p>
<div class="container">
<div class="header"></div>
<div class="two_main">
<div class="left"></div>
<div class="right"></div>
<div class="cen">主题内容</div>
</div>
<div class="footer"></div>
</div>
</body>
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