eCart add button and javascript form

I have a form that I have used javascript to evaluate options and push a price into the input price form. Now I need to add an add-to-cart button so I can put the product into the cart. The problem I am running into when I go to add the button it will not allow me to add it to the existing form with the <form name="orderForm" ?> as I have it. It wants to use <form name="eCart_1_ATC_<?php echo $row_rsProduct["productid"]; ?>". Now I do not know enough about javascript to know what the exact form name is in javascript. Before I had document.orderForm.formPrice for the name in the form. So I need help in identifying the form name for javascript. I know this is not correct document.eCart_1_ATC_<?php echo $row_rsProduct["productid"]; ?>.formPrice or at least it is not working for me.

Your help is appreciated.