Add a quick "donation" (or "tip") field as a payment module on a checkout page?

[troubador]

Hi folks,

First, thanks for this splendid program. I've done a few oscommerce sites, and I think the improvements y'all have done are splendid.

I'm running a "plain vanilla" Zen Cart v1.3.8a/v1.3.8, haven't installed any modules or touched anything except template overrides. I'd like to keep it this way, and I'm comfortable with PHP, so here's my question: how hard would it be to add a "donation" box on one of the payment page? Just an additional box that someone could type an amount into on their way out, and have the amount added to the total? I'm designing a site for a non-profit client, and he requested this feature.

I really appreciate any pointers in the right direction. I found in the forums a suggestion about making a donation "product," but I think it will work better for us if the customer can just type in an amount, and recalculate the subtotal.

Thanks very much,
Bill

[bonnit]

i would quite like to do this too, did you ever find out how? thanks.