一、relative依据自身定位
二、absolute依据最近一层的定位元素定位
定位元素有：
- relative、absolute、fixed
- body （向上查找没有找到定位元素，就会依据body定位）
三、案例
<!DOCTYPE html>
<html>
<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>absote relative 定位问题</title>
<style type="text/css">
body {
margin: 20px;
}
.relative {
position: relative;
width: 400px;
height: 200px;
border: 1px solid #ccc;
top: 20px;
left: 50px;
}
.absolute {
position: absolute;
width: 200px;
height: 100px;
border: 1px solid blue;
top: 20px;
left: 50px;
}
</style>
</head>
<body>
<p>absolute 和 relative 定位问题</p>
<div class="relative">
<div class="absolute">
this is absolute
</div>
</div>
</body>
</html>
标签：body,定位,relative,20px,依据,absolute From： https://www.cnblogs.com/hjbky/p/17159326.html