Client Side Validation on CustomValidator

Hi all,

I am creating a custom validator for three check boxes. at least one has to be checked. I have created the server side script and thats working fine. However i need to create the client side script and i have no clue in JavaScript. So would really appreciates somones help. The Checkboxes are in a FormView contol if that makes any difference?? This is my totally messed up code below:-
1 <script type="text/javascript" language="javascript">
2 function CusValLearn(source, args) {
3 Var ChkSpeak = document.forms["FormView1"].elements["CheckBoxSpeak"];
4 Var ChkWrite = document.forms["FormView1"].elements["CheckBoxWrite"];
5 Var ChkTran = document.forms["FormView1"].elements["CheckBoxTran"];
6 if ChkSpeak.Checked (
< ...