help making very simple form

hi anyone help me make a very simple form for my site.

i can pay if its going to cost.

i need a simple form:

box1 - select item ( list of 10 items )
box2 - number of months ( 1 to 12 )

box 3 outputs a number based on box1 and 2

basiclly each item in box1 costs x amount then multiplied by box 2

thanks

 

When box 1 and box 2 change have it call to your JavaScript function to check to see if both have value, and if so have it do the math and use innerHTML to place the value into box 3.. quite simple actually are you still needing help on this or have you gotten it by now?

 

thanks. no have not managed it yet but have the graphics etc sorted lol.