The following function adds a class called bar for all paragraphs (p) that have a class named foo

Edit code and click me	Your Result (Some examples do not work in Google Chrome):
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <script src="http://code.jquery.com/jquery-latest.js"></script> <script type="text/javascript" language="javascript"> $(document).ready(function(){ $("button").click(function () { $("p.foo").addClass("bar"); }); }); </script> <style type="text/css"> .foo {color:red;} .bar {font-weight:bold;} </style> </head> <body style="font-family:Arial, Helvetica, sans-serif;color:#3c3c3c;"> <button>Add class bar only to paragraphs with class foo</button><br/> <p class="foo">I'm paragraph with class name 'foo'</p> <p>I'm paragraph without class name 'foo'</p> <p class="foo">I'm paragraph with class name 'foo' too</p> class bar indicated in bold </body> </html>
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