源代码:
<!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>Wfuyu教程(wfuyu.com)</title> <style> h1:before {content:url(/statics/images/course/smiley.gif);} </style> </head> <body> <h1>This is a heading</h1> <p>The :before pseudo-element inserts content before an element.</p> <h1>This is a heading</h1> <p><b>注意:</b>仅当 !DOCTYPE 已经声明 IE8 支持这个内容属性</p> </body> </html>
运行结果：