5.1 相对定位
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>相对定位</title>
<!--相对定位：
相对于自己原来的位置进行偏移
-->
<style>
body{
padding: 20px;
}
div{
margin: 10px;
padding: 5px;
font-size: 18px;
line-height: 25px;
}
#father{
border: 1px solid #666;
padding: 0;
}
#first{
background: #5f85ff;
border: 1px dashed orange;
position: relative;
top: -10px;
left: 20px;
}
#second{
background: #21D4FD;
border: 1px dashed yellowgreen;
}
#third{
background: #ff23bd;
border: 1px dashed limegreen;
position: relative;
bottom: -10px;
right: 20px;
}
</style>
</head>
<body>
<div id="father">
<div id="first">第一个盒子</div>
<div id="second">第二个盒子</div>
<div id="third">第三个盒子</div>
</div>
</body>
</html>相对定位：position: relative;
相对于原来的位置，进行指定的偏移（它任然在标准文档流中，原来的位置会被保留）
top: -10px;
bottom: -10px;
left: 20px;
right: 20px;Demo：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<style>
#box{
width: 300px;
height: 300px;
padding: 10px;
border: 1px solid red;
}
a{
width: 100px;
height: 100px;
text-decoration: none;
background: lightblue;
line-height: 100px;
text-align: center;
color: white;
display: block;
}
a:hover{
background: lightsalmon;
}
.a2,.a4{
position: relative;
left: 200px;
top: -100px;
}
.a5{
position: relative;
left: 100px;
top: -300px;
background: #5f85ff;
}
</style>
</head>
<body>
<div id="box">
<a class="a1" href="#">链接1</a>
<a class="a2" href="#">链接2</a>
<a class="a3" href="#">链接3</a>
<a class="a4" href="#">链接4</a>
<a class="a5" href="#">链接5</a>
</div>
</body>
</html>
5.2 绝对定位
基于xxx定位：上下左右
1、在没有父级元素定位的情况下，相对于浏览器定位
2、父级元素定位存在时，相对于父级元素进行偏移
3、在父级元素范围内移动
相对于父级或浏览器的位置进行指定偏移，绝对定位后，不在标准文档流中，原来的位置不被保留
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<style>
div{
margin: 10px;
padding: 5px;
font-size: 18px;
line-height: 25px;
}
#father{
border: 1px solid #666;
padding: 0;
position: relative;
}
#first{
background: #5f85ff;
border: 1px dashed orange;
}
#second{
background: #21D4FD;
border: 1px dashed yellowgreen;
position: absolute;
left: 2px;
}
#third{
background: #ff23bd;
border: 1px dashed limegreen;
}
</style>
</head>
<body>
<div id="father">
<div id="first">第一个盒子</div>
<div id="second">第二个盒子</div>
<div id="third">第三个盒子</div>
</div>
</body>
</html>5.3 固定定位
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<style>
body{
height: 1200px;
}
/*绝对定位：相对于浏览器*/
div:nth-of-type(1){
width: 100px;
height: 100px;
background: red;
position: absolute;
right: 0;
bottom: 0;
}
/*fixed 固定定位*/
div:nth-of-type(2){
width: 50px;
height: 50px;
background: yellow;
position: fixed;
right: 0;
bottom: 0;
}
</style>
</head>
<body>
<div>div1</div>
<div>div2</div>
</body>
</html>
5.4 z-index
图层
opacity: 0.5; 背景透明度
#content{
width: 500px;
padding: 0;
margin: 0;
overflow: hidden;
font-size: 18px;
line-height: 25px;
border: 1px solid black;
}
ul,li{
padding: 0;
margin: 0;
list-style: none;
}
/*父级元素相对定位*/
#content ul{
position: relative;
}
.tipText,.tipBg{
position: absolute;
width: 500px;
height: 25px;
top: 401px;
}
.tipText{
color: white;
/*z-index: 999;*/
}
.tipBg{
background: black;
opacity: 0.5;/*背景透明度*/
filter: alpha(opacity=50);/*IE8及以前用filter代替opacity*/
}<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<link rel="stylesheet" href="css/style.css" type="text/css">
</head>
<body>
<div id="content">
<ul>
<li><img src="image/bg.jpg" alt=""></li>
<li class="tipText">强风吹拂！</li>
<li class="tipBg"></li>
<li>时间：16点31分</li>
<li>地点：bilibili</li>
</ul>
</div>
</body>
</html>
评论 (0)