X-Cart forums - Product Options Dropdown Validation onChange

Hello friends

I have a store with a few products (ladders), each ladder has a unique configuration, if you want please see this:

http://www.peldanos.com/portal/product.php?productid=1&cat=0&bestseller=Y

If you see I have 3 product options, for example:

Option 1:
a
b
c
d

Option 2:
a
b
c
d

Option 3:
a
b
c
d

What I need is that the only configurations avilable are: "aaa", "bbb","ccc" and "ddd" I mean, if the user in the Option 1 select "a" then the Option 2, the Option 3 change to "a" also...

I think I could modify it with javascript, and I have some ideas but I don╢t know exactly how to apply this in X-Cart.. but, I have also see that if I change the template customer_options.tpl I can achieve this in all the store but I don't know exactly how to do it.. could some body helpme???

I think if I can set a function in "onChange" of each option and set something like this??.. I don't know??

Code:

<script language="javascript">

function check_options(select)

{

{foreach from=$product_options item=v}

var {$v.class} = document.getElementById('po{$v.classid}');

{/foreach}



switch(select)

{

case 1:

switch({$v.class}.value)

{

case '2':

{$v.class}.value = '{$o.optionid}';

{$v.class}.value = '{$o.optionid}';

break;

}



}

}

</script>

PLEASE, I REALLY NEED HELP !

THANKYOU!!