[Zope] form arrays?

When I add an onclick=window.open to my form, the entire form array is presented in REQUEST, rather than just "this" form that was clicked. Just "this" form is presented without the javascript. How can I get the selected color of just the product I clicked on? How does the addition of javascript change the "post" of the form from "this" (clicked) form to the entire array of forms on the page?