向第一个 p 元素添加一个类
This is a heading
This is a paragraph.
This is another paragraph.
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1 <html> 2 <head> 3 <script type="text/javascript" src="/jquery/jquery.js"></script> 4 <script type="text/javascript"> 5 $(document).ready(function(){ 6 $("button").click(function(){ 7 $("p:first").addClass("intro"); 8 }); 9 }); 10 </script> 11 <style type="text/css"> 12 .intro 13 { 14 font-size:120%; 15 color:red; 16 } 17 </style> 18 </head> 19 20 <body> 21 <h1>This is a heading</h1> 22 <p>This is a paragraph.</p> 23 <p>This is another paragraph.</p> 24 <button>向第一个 p 元素添加一个类</button> 25 </body> 26 </html>
