<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>右侧导航菜单练习</title>
<link rel="stylesheet" href="css/main.css">
<script src="js/main.js"></script>
</head>
<body>
<button>按钮</button>
<div class="testCenter">
<div class="testCenter2">
<div class="testCenter3">
<div class="testCenter4">
</div>
</div>
</div>
</div>
</body>
</html>
/*
1: block = inline-block + width:100%
2: inline-block = inline + 换行
3: inline情况下，height和width都不起作用
4: padding的垂直效果 = display不能为inline
*/
.testCenter {
position: absolute;
width: 500px;
height: 500px;
background-color: red;
border: solid 1px yellow;
left: 0;
right: 0;
top: 0;
bottom: 0;
margin: auto;
}
/*推荐用法*/
.testCenter2 {
position: absolute;
width: 400px;
height: 400px;
background-color: green;
left: 50%;
top: 50%;
margin: -200px 0 0 -200px;
}
.testCenter3 {
position: absolute;
width: 300px;
height: 300px;
background-color: royalblue;
left: 50%;
top: 50%;
transform: translate(-50%, -50%);
/*设置这三个属性，子元素就能居中了，ie11以下不支持*/
justify-content: center;
align-items: center;
display: flex;
}
.testCenter4 {
width: 200px;
height: 200px;
background-color: yellow;
}
下一篇要看阮老师的flex布局，弹性布局。
http://www.ruanyifeng.com/blog/2015/07/flex-grammar.html
转载请注明原文地址: https://ju.6miu.com/read-662.html
