That is exactly what I wanted, thank you. How is your experience with it?

I quickly tried it out with websites like Amazon, it seems to cover the whole website instead of individual items, but even then the chats are old and doesn't seem to have active users. Perhaps it is the 'chicken and egg' problem Abishek was telling about in another comment?

Anyways, this is the best solution for this problem so far. I hope many people use it.