Payment from variable amount

Thank you for your help however I must be doing something completely wrong. So I decided to paste one of your examples in and even this comes up with errors!

Well of course it will do as you have simply just copied the code and pasted it straight into the site code tab.

The parts where it says backend code should be placed in a jsw file in your backend whilst the client side code should be placed on the page that you are using it on.

I would suggest that you read up about using backend files, as stated in the already linked pages in previous post.