Question about adding event handler to a TextBox inside a TabContainer

Question about adding event handler to a TextBox inside a TabContainer

I have a TabContainer on my page, and I want to add a keyup handler to the textbox, but somehow I counldn't find the textbox in my jquery function using  $('#TabContainer1_TabPanel1_TextBox1').

How to fix my code to make it work? Here is my code:
  2. <html xmlns="http://www.w3.org/1999/xhtml" >
  3. <head runat="server">
  4.     <title></title>
  5.     <script type="text/javascript" src="js/jquery-1.3.2.min.js" >    
  6.         $(document).ready(function(){
  7.             $('#TabContainer1_TabPanel1_TextBox1').keyup(function(event){
  8.                 alert('Hello!');            
  9.             });        
  10.         });      
  11.     </script>
  12. </head>
  14. <body>
  15.     <form id="form1" runat="server">
  16.     <div>
  17.         <asp:ScriptManager ID="ScriptManager1" runat="server" />        
  18.         <cc1:TabContainer ID="TabContainer1" runat="server" ActiveTabIndex="0"             AutoPostBack="false">
  19.             <cc1:TabPanel runat="server" ID="TabPanel1">
  20.                 <ContentTemplate>                          
  21.                     <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
  22.                 </ContentTemplate>  
  23.             </cc1:TabPanel>
  24.         </cc1:TabContainer>
  25.     </div>
  26.     </form>
  27. </body>
  28. </html>