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HomeWeb Front-endHTML TutorialCSS概述<选择器总结>_html/css_WEB-ITnose

概述:CSS是指层叠样式表,他是定义如何显示HTML元素,样式表通常存储在样式表中,通常存储在.css文件中,下面对css的选择器进行总结,便大家夯实基础!

1 语法规范:

每个样式规则有两个部分:选择器和样式声明

2 CSS规则特性:继承性,层叠,后定义样式优先:

3 CSS选择器

4.1 元素选择器:选择所有同名的元素

4.2 类选择器:元素中可以定义相同的类,同时类选择器通常和id选择器互补共用

4.3 id选择器:元素选择器中可以定义不同的id,id选择器保持元素个性

4.4 派生选择器:根据上下级关系选择元素

4.5 伪类选择器:元素的不同状态,用于相应鼠标滑动事件

4.6选择器分组,不同id的选择器用逗号隔开

index.html源码:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8" /><title>无标题文档</title></head>    <link rel ="stylesheet" href="index.css"><body><div id="header"><a>退出</a></div><div id="navi">此处显示  id "navi" 的内容</div><div class="main">此处显示    class "main" 的内容</div><div id="operate" class="subdiv">此处显示  class "operate" 的内容</div><div id="data" class="subdiv">此处显示  id "data" 的内容</div><div id="pages" class="subdiv">此处显示  id "pages" 的内容</div><div id="footer">    <p>版权所有&copy;加拿大达内IT培训公司</p></div></body></html>

index.css

/*元素选择器:选择所有同名的元素*/div{        border:2px solid blue;    margin:0 auto;    }/*id选择器*/#header{height:61px; text-align:right}#navi{width:100%;height:91px;}#main{width:950px; height:410px; border:5px solid#8ac1db}#footer{height:50px; }/*类选择器补充不同的样式*/.subdiv{width:910px;}#operate{height:30px}#data{height:340px}#pages{height:28px}/*选择器分组,临时发现个别元素具有相同的属性*/#header,#footer{width:960px}#header a{         text-decoration:none         color:blue;         line-height:61px /*行高等于容器高度*/        }/*选择器派生:根据上下级关系选择元素时*/#footer p{text-align:center}/*伪类:元素的不同状态*/#header a:hover{ font-size:20px}/*鼠标滑过*/#header a:active{ color:red}/*鼠标按下时候*/

 

程序截图:

 

5其他的样式:

其他的小细节:1如果需要设置容器内部垂直居中,小技巧是:设置行高等于容器高度,例如 line-height:61px /*行高等于容器高度*/

                    2如果需要相应鼠标事件,一般用伪类,并且hover,action这两个经常用,例如:/*伪类:元素的不同状态*/ #header a:hover{ font-size:20px}/*鼠标滑过*/ #header a:active{ color:red}/*鼠标按下时候*/

 

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