I am allowing users to choose which payment system they wish on a form. However if no deposit is required I remove this radio button and only display the full payment radio button. Problem is the function I am using to show the radio buttons (ie. turn disable = false) fails because the deposit radio button does not exist!!

This is the function:

function FlipBoxes() {
if (document.Form2.PaymentType[1].checked) { document.Form2.PaymentAmount[1].disabled = false document.Form2.PaymentAmount[0].disabled = false } else { document.Form2.PaymentAmount[1].disabled = true document.Form2.PaymentAmount[0].disabled = true
}
}

So how do i detect whether the radio button exists? I have tried:
if (document.Form2.PaymentAmount[0])
to no avail..

Please help this is driving me crazy...