>>See this blog too http://weblogs.asp.net/SteveWellens/ (the second blog).
>
>I am not sure what you want me to look for at that page. Can you explain more?

The second blog lists this

Here is my first jQuery code: 

    <script type="text/javascript" src="jquery.js"></script>             <script type="text/javascript">         // ---- After document is loaded, run this -----         $(document).ready(            function()            {                               MyJScript();            }        )         // ---- MyJScript -------------------------         function MyJScript()        {            // get all TextBoxes with class MyInput            var TextBoxes = $(".MyInput");             // if any TextBoxes are blank, set the            // background color to yellow            TextBoxes.each(                function Yellowize()                {                    if (this.value == "")                        this.style.backgroundColor = "yellow";                }            )        }     </script>

which I think somehow related to your problem, though it shows how to find controls of certain type in client-side code.