效果：

 

 

代码：

    
     	       
     
      
      
伪元素选择器
      
      
首页
    
     
    
     
         
      
::before,::after
         
      
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                       Sunlike阿理旺旺Sunlike阿理旺旺Sunlike阿理旺旺Sunlike阿理旺旺Sunlike阿理旺旺                Sunlike阿理旺旺Sunlike阿理旺旺Sunlike阿理旺旺Sunlike阿理旺旺Sunlike阿理旺旺                 Sunlike阿理旺旺Sunlike阿理旺旺Sunlike阿理旺旺Sunlike阿理旺旺Sunlike阿理旺旺                 Sunlike阿理旺旺Sunlike阿理旺旺Sunlike阿理旺旺Sunlike阿理旺旺Sunlike阿理旺旺                Sunlike阿理旺旺Sunlike阿理旺旺Sunlike阿理旺旺Sunlike阿理旺旺Sunlike阿理旺旺         
      
    
     

　　总结：

1、first-letter： 获取第一个字母或中文字；

2、first-line：给block，inline-block，table-capttion，table-cell元素提供选取第一行元素的功能；

3、::before,::after：给元素添加额外的块；

4、selection：被选中的文本内容。