案例一：
隐藏扩展域，并去掉after，并去掉高度
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Title</title>
<style>
.clearfix:after{ /*善用after和defore*/
content: "111"; /*注意加引号*/
clear: both;
display: block;
visibility: hidden; /*隐藏并有高度*/
height: 0; /*去掉高度*/
}
.c{
width: 100px;
/*height: 100px;*/
background-color:red;
}
.c .item{
float:left;
width:30px;
background-color: green ;
}
</style>
</head>
<body>
<div class='c clearfix'>
<div>123</div>
<div>456</div>
</div>
<div>内容</div>
</body>
</html>
案例二：
当鼠标放在一个图片上显示这个商品的信息，或者一些别的东西，比如
.touch:hover .content{}
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<style>
.touch{
width: 200px;
height: 200px;
overflow: hidden;
position: relative;
}
.touch .content{
position: absolute;
left: 0;
top: 0;
right: 0;
bottom: 0;
background-color: rgba(0, 0, 0,.6);
color: white;
text-align: center;
visibility: hidden;
}
.touch:hover .content{
visibility: inherit;
}
</style>
</head>
<body>
<div class="touch">
<div><img src="2.jpg"></div>
<div class="content">
<div class="c1">ALEX</div>
<div class="c1">500-1000(日)</div>
</div>
</div>
</body>
</html>
案例三：
要求在当前页面不超出多余内容，超出了变成滚动条显示
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<style>
body{
margin: 0;
}
.pg_top{
height: 48px;
background-color: #dddddd;
}
.pg_body_menu{
position: absolute;
width: 180px;
background-color: blueviolet;
left: 0;
}
.pg_body_content{
position: absolute;
top: 48px;
left: 190px;
right: 0;
bottom: 0;
background-color: blueviolet;
overflow: auto; /*可以利用overflow变导航条*/
}
</style>
</head>
<body>
<div class="pg_top">
</div>
<div class="pg_body">
<div class="pg_body_menu">
<p>1</p><p>1</p><p>1</p><p>1</p><p>1</p>
<p>1</p><p>1</p><p>1</p><p>1</p><p>1</p>
<p>1</p><p>1</p><p>1</p><p>1</p><p>1</p>
</div>
<div class="pg_body_content">
<p>1</p><p>1</p><p>1</p><p>1</p><p>1</p>
<p>1</p><p>1</p><p>1</p><p>1</p><p>1</p>
<p>1</p><p>1</p><p>1</p><p>1</p><p>1</p>
<p>1</p><p>1</p><p>1</p><p>1</p><p>1</p>
<p>1</p><p>1</p><p>1</p><p>1</p><p>1</p>
<p>1</p><p>1</p><p>1</p><p>1</p><p>1</p>
</div>
</div>
</body>
</html>
案例四：
尖角图标，尖角符号是向上，当鼠标点的时候尖角符号向下
.c1{ /*这个是麻烦写法*/
border-top: 30px solid yellow ;
border-left: 30px solid green;
border-bottom: 30px solid blue;
border-right: 30px solid black;
display: inline-block;
}
.c1{ /*半个*/
border-top: 30px solid yellow ;
border-left: 30px solid green;
border-bottom: 0px solid blue;
border-right: 30px solid black;
display: inline-block;
}
完整代码：
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<style>
/*.c1{ 这个是麻烦写法
border-top: 30px solid yellow ;
border-left: 30px solid green;
border-bottom: 0px solid blue;
border-right: 30px solid black;
display: inline-block;
}*/
.c1{
border: 30px solid transparent ;
border-top: 30px solid yellow ;
display: inline-block;
margin-top: 40px;
}
.c1:hover{
border: 30px solid transparent;
border-bottom: 30px solid yellow ;
margin-top:10px ;
}
</style>
</head>
<body>
<div style="height: 150px; background-color: red;">
<div class="c1"></div>
</div>
</body>
</html>
案例五：
模态对话框
就是弹出一个框，然后显示一些内容（其实是分为三层）
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<style>
body{
margin: 0;
}
.model{
position: fixed;
top: 0;
right: 0;
bottom: 0;
left: 0;
background-color: rgba(0,0,0,0.5);
z-index: 2;
}
.content{
height: 300px;
width: 400px;
background-color: white;
color: #000000;
position: fixed;
top: 50%;
left: 50%;
z-index: 3;
margin-left: -200px;
margin-top: -200px;
font-size:32px ;
line-height: 300px;
text-align: center;
}
</style>
</head>
<body>
<div style="height: 2000px; background-color: red;">
<h1>ads</h1><h1>ads</h1><h1>ads</h1><h1>ads</h1><h1>ads</h1>
<h1>ads</h1><h1>ads</h1><h1>ads</h1><h1>ads</h1><h1>ads</h1>
</div>
<div class="model"></div>
<div class="content">悲伤那么大！！！</div>
</body>
</html>
案例六：
输入框里面有图片
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<style>
.user{
position: relative;
width: 250px;
}
.user input{
height: 30px;
width: 150px;
padding-right: 20px;
}
.user .ren{
position: absolute;
top: 8px;
left: 160px;
}
</style>
</head>
<body>
<div class="user">
<input type="text" />
<span class="ren">R<!--这里可以放图片--></span>
</div>
</body>
</html>
案例七：
商品加减框
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<style>
body{
margin: 0;
}
.left{
float: left;
}
.wrap{
width: 150px;
height: 22px;
border: 1px solid #ddd;
/*background-color: red;*/
position: relative;
left: 100px;
top: 100px;
}
.wrap .minus{
height: 22px;
width: 22px;
line-height: 22px;
text-align: center;
}
.wrap .plus{
height: 22px;
width: 22px;
line-height: 22px;
text-align: center;
}
.wrap .count input{
padding: 0; /*input是有padding的*/
border: 0;
width: 104px;
height: 22px;
border-left: 1px solid #dddddd;
border-right: 1px solid #dddddd;
}
</style>
</head>
<body>
<div class="wrap">
<div class="minus left">-</div>
<div class="count left">
<input type="text" />
</div>
<div class="plus left">+</div>
</div>
</body>
</html>
案例八：
商品加减框加减，鼠标并变化样式
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<style>
body{
margin: 0;
}
.left{
float: left;
}
.wrap{
width: 150px;
height: 22px;
border: 1px solid #ddd;
/*background-color: red;*/
position: relative;
left: 100px;
top: 100px;
}
.wrap .minus{
height: 22px;
width: 22px;
line-height: 22px;
text-align: center;
cursor: pointer;
}
.wrap .plus{
height: 22px;
width: 22px;
line-height: 22px;
text-align: center;
cursor: pointer; /*当鼠标指的时候变样式*/
}
.wrap .count input{
padding: 0; /*input是有padding的*/
border: 0;
width: 104px;
height: 22px;
border-left: 1px solid #dddddd;
border-right: 1px solid #dddddd;
}
</style>
</head>
<body>
<div class="wrap">
<div class="minus left" onclick='Minus();'>-</div>
<div class="count left">
<input id='count' type="text" />
</div>
<div class="plus left" onclick='Plus();'>+</div>
</div>
<script type="text/JavaScript">
function Plus(){
var old_str = document.getElementById('count').value
var old_int = parseInt(old_str);
var new_int = old_int + 1
document.getElementById('count').value = new_int
}
function Minus(){
var old_str = document.getElementById('count').value
var old_int = parseInt(old_str);
var new_int = old_int - 1
document.getElementById('count').value = new_int
}
</script>
</body>
</html>
案例九：
当鼠标指到图片，会变成字体和边框颜色会变
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<style>
.ele{
width: 300px;
height: 300px;
background-color: yellow;
}
.ccc{
width: 300px;
height: 200px;
background-color: green;
}
.ddd{
width: 300px;
height: 100px;
background-color: red;
}
.ele:hover .ddd{
background-color: blueviolet;
font-size: 38px;
}
</style>
</head>
<body>
<div class="ele">
<div class="ccc">图片1</div>
<div class="ddd">
ddd
</div>
</div>
</body>
</html>
本文转自：https://www.cnblogs.com/renfanzi/p/5641978.html
