Dynamic Form Fields

Need some Javascript help...

I have a script I use for inputting recipes...I want to roll it out to my site visitors but I would like a way for them to easily add ingredients to recipes that they submit using my "Recipe Adder" form...

So initially they have a form where they can enter a recipe and just one ingredient, but there's a button that "Adds Ingredient" and thus inserts a new form field for another ingredient for them to fill in...

make sense...?

IMO, the only way to this using Javascript is to prepare all the fields you can ever need in advance. Then you can set their visibility attribute to invisible and every time user clicks on an add ingredient button you will set one more field to visible.