运行 ❯
获取您
自己的
网站
×
更改方向
保存代码
更改主题,深色/浅色
前往 Spaces
<!DOCTYPE html> <html> <head> <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.7.1/jquery.min.js"></script> <script> $(document).ready(function(){ $("button").click(function(){ $("p:first").addClass("intro note"); }); }); </script> <style> .intro { font-size: 30px; color: blue; } .note { background-color: yellow; } </style> </head> <body> <h1>This is a heading</h1> <p>This is a paragraph.</p> <p>This is another paragraph.</p> <button>Add two class names to the first p element</button> </body> </html>