Form with dynamic entry fields and validation

Users to complete a textbox with their name, a textbox with their email address and select a number from 1 to 20 in a combo box (let's call this number - 'x'). On submitting the form, it posts to itself and displays the three inputs PLUS x times two more textboxes, one for name [default text - 'please enter name'] and one for email [default text - 'please enter email address']. On submission, form to check that something other than default text has been entered in each textbox.