Where can I find details of AddToCart() parameters / variables?

The BUY NOW button won't work with Products that have a minimum quantity > 1 (so Support advises). My client prefers the BUY NOW button, I'm trying figure out a way to either replace the button (for those were it won't work) or update the addtocart() code.

I found a reference to custom JS and AddToCart(catalogueId, productId, frame, details, buynow, options) being replaced with AddToCart(catalogueId, productId, frame, details, ‘’,’’, buynow, options) in BC Status from about a year ago - but where can I find more information on what these parameters are??

Thanks,

Suze