I am new to bitcoin technology, I want to build Bitcoin payment button with 2 bitcoin addresses, first is my site address where I will receive a small commission fee, second is my site seller address. When a customer pay, bitcoins will be send to both addresses, is that possible? Thanks
It's possible, but difficult to do with standard wallets. What you can do is have a third address that your clients will see, and when you receive bitcoins there, then split them to the other two addresses that you want.
The other answer is correct, you could receive in a single address and in the back-end automatically split it to your two addresses. Or receive into your personal wallet and automatically send a bit to the commission address.
A bitcoin: link (click or QR) can include the address & amount and most wallets will allow you to pay more than one address in a single transaction but this would rely on the user scanning two QR codes so it's not ideal. I'm pretty sure that while the QR tech can handle it you can't include two addresses in a bitcoin: link/QR.