[Javascript] addin <input fields> via visibility or similar?

[Michael Borchers]

i have form 
for several products.

the products data is stored in arrays.

normally i have about 5 rows.

<select name="products_id[0][products_id]" id="products_id[0][products_id]">
...
</select>
<input type="text" name="products_id[0][products_price]" id="products_id[0][products_price]" value="0,00">
<input type="text" name="products_id[0][products_quantity]" value="" size="6" maxlength="3">

until products_id[4] of course.

now  i would like to have an extra input field for adding X rows and make them visible
in the form without reloading the page.
is this possible with visible layers or even without preloading rows and generating
them on the fly?

thanks!