ID selector only
<html> <head> <script type="text/javascript" src="js/jquery-1.3.2.js"></script> <style type="text/css"> .changeP { font-weight: bold; color:red;} </style> <script type="text/javascript"> $(document).ready(function(){ $("#myID").css("border","3px solid red"); }); </script> </head> <body> <div id="myID">0</div> <div id="myID1">1</div> <div id="myID2">2</div> </body> </html>