51help TIY
码：
<!DOCTYPE html> <html> <head> <script src="../../ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js" tppabs="http://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"> </script> <script> $(document).ready(function(){ $("button").click(function(){ $("#div1").addClass("important blue"); }); }); </script> <style type="text/css"> .important { font-weight:bold; font-size:xx-large; } .blue { color:blue; } </style> </head> <body> <div id="div1">本。</div> <div id="div2">本。</div> <br> <button>向第一个 div </button> </body> </html>
查看结果: