Dynamically creating textbox in form?



What I’m trying to hack up is a form that has a portion which would
allow me to add “any number” of another set of items.

For instance when specifying a product in a table, and this said product
can have a number of ways which it can be delivered, so I will have a
“Add additional delivery method” javascript link, which when clicked
will create an additional set of textboxes for a new “delivery method”.

Is it possible to edit _form.rhtml to achieve this effect once I’ve
decided on the javascript code that I’d use to achieve this?