Effect: on one page or a certain type of element selected
1. Basic selector
1. tag selector: Select a category label tag {}
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<style>
/*标签选择器,会选择到页面上所有的这个标签的元素*/
h1{
color: #a13d30;
background: #3cbda6;
border-radius: 24px;
}
p{
font-size: 80px;
}
</style>
</head>
<body>
<h1>学Java</h1>
<h1>学Java</h1>
<p>听狂神说</p>
</body>
</html>
2. Class Selector class: Select all of the same class attribute labels, tags across the class name {}.
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<style>
/*类选择器的格式 .class的名称{}
好处,可以多个标签归类,是同一个 class,可以复用
*/
.yy{
color: #3748ff;
}
.xn{
color: #a24fff;
}
</style>
</head>
<body>
<h1 class="yy">标题1</h1>
<h1 class="ly">标题2</h1>
<h1 class="xn">标题3</h1>
<p class="kl">P标签</p>
</body>
</html>
3.Id selector: Globally Unique! #id name} {
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<style>
/* id选择器 : id必须保证全局唯一!
#id名称{}
优先级:
不遵循就近原则,固定的
id选择器> class 选择器 > 标签选择器
*/
#yy{
color: #ff008a;
}
.style1{
color: #02ff00;
}
h1{
color: #2d1dc1;
}
</style>
</head>
<body>
<h1 class="style1" id="yy">标题1</h1>
<h1 class="style1">标题2</h1>
<h1 class="style1">标题3</h1>
<h1>标题4</h1>
<h1>标题5</h1>
</body>
</html>
Priority: id> class> tag
2. level selector
1. Priority: id> class> tag
/*后代选则器*/
body p{
background: red;
}
2. The child selector, generation, son
/*子选择器*/
body>p{
background: #3cbda6;
}
3. adjacent sibling selector peers
/*相邻弟选择器: 只有一个,相邻(向下) */
.active + p{
background: #a13d30;
}
4. universal selector
/*通用兄弟选则器,当前选中元素的向下的所有兄弟元素*/
.active~p{
background: #02ff00;
}
3. Structure pseudo class selector
p:first-child | Select all the elements of the first child element p |
---|---|
p:last-child | Select all p elements of last child |
p:nth-child(2) | Select the parent element of all the p elements of the second child element |
p:nth-of-type(2) | Select all p elements is the second child element p |
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<!--避免使用,class,id选择器-->
<style>
/*ul的第一个子元素*/
ul li:first-child{
background: #02ff00;
}
/*ul的最后一子元素*/
ul li:last-child{
background: #ff4832;
}
/* 选中 p1 : 定位到父元素,选择当前的第一个元素
选择当前p元素的父级元素,选中父级元素的第一个,并且是当前元素才生效! ,顺序
*/
p:nth-child(1){
background: #2700ff;
}
/*选中父元素,下的p元素的第二个,类型 */
p:nth-of-type(2){
background: yellow;
}
</style>
</head>
<body>
<!--<a href="">31231</a>-->
<!--<h1>h1</h1>-->
<p>p1</p>
<p>p2</p>
<p>p3</p>
<ul>
<li>li1</li>
<li>li2</li>
<li>li3</li>
</ul>
</body>
</html>
4. attribute selector
= Absolute equal | * = Include this element |
---|---|
This begins with ^ = | To this end = $ |
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<style>
.demo a{
float: left;
display: block;
height: 50px;
width: 50px;
border-radius: 10px;
background: #2700ff;
text-align: center;
color: gainsboro;
text-decoration: none;
margin-right: 5px;
font: bold 20px/50px Arial;
}
/* 属性名, 属性名 = 属性值(正则)
= 绝对等于
*= 包含这个元素
^= 以这个开头
$= 以这个结尾
*/
/*存在id属性的元素 a[]{}*/
/*a[id]{*/
/*background: yellow;*/
/*}*/
/*id=first的元素*/
/*a[id=first]{*/
/*background: #63ff23;*/
/*}*/
/*class 中有 links的元素*/
/*a[class*="links"]{*/
/*background: yellow;*/
/*}*/
/*!*选中href中以http开头的元素*!*/
/*a[href^=http]{*/
/*background: yellow;*/
/*}*/
a[href$=jpg]{
background: yellow;
}
</style>
</head>
<body>
<p class="demo">
<a href="http://www.baidu.com" class="links item first" id="first">1</a>
<a href="http://blog.kuangstudy.com" class="links item active" target="_blank" title="test">2</a>
<a href="images/123.html" class="links item">3</a>
<a href="images/123.png" class="links item">4</a>
<a href="images/123.jpg" class="links item">5</a>
<a href="abc" class="links item">6</a>
<a href="/a.pdf" class="links item">7</a>
<a href="/abc.pdf" class="links item">8</a>
<a href="abc.doc" class="links item">9</a>
<a href="abcd.doc" class="links item last">10</a>
</p>
</body>
</html>