This document describes how bidding works in a 20-second auction for an iPhone on Bidder.co.uk. The bidding timeline is updated every 5 seconds, showing the highest bid and price. If a bid is placed within 11 seconds of the end, the user won't see it until the next 5-second update. In the final 2 seconds, the item enters "CHECK" mode where the timer extends to allow time to receive and process any last bids.

1. How CHECK works?

2. As example here is the
case of an iphone 20
seconds auction.

3. iPhone 20 seconds auction
We create a timeline
that indicates 20
seconds

4. Every 5 seconds your
computer ask
Bidder.co.uk for an
update.
The Update contains:
Highest bidder and latest
price

5. iPhone 20 seconds auction
update update update update

6. iPhone 20 seconds auction
5 seconds 5 seconds 5 seconds
update update update update
Update is always every 5 seconds.

7. iPhone 20 seconds auction
update update update update
BID
Here is the example of a Bid made 11 seconds
before the end.

8. iPhone 20 seconds auction
update update update update
BID
You don’t see that bid until your computer updates
thus at 8 seconds before the end.

9. iPhone 20 seconds auction
update update update update
BID
In the moment you receive the update the timer
restarts, but not at 20 seconds, at 17 seconds.

10. The same thing happens in the
last 4 seconds, only it is called
CHECK

11. iPhone 20 seconds auction
update update update update
BID
Here is the example of a Bid made 2 seconds
before the end.

12. iPhone 20 seconds auction
update update update update update
BID
The next update will be at minus 2 seconds.
This means that the timer goes to 0.1 and in
CHECK for 2 seconds.

13. iPhone 20 seconds auction
update update update update update
BID
In the moment you receive the update the timer
restarts, but not at 20 seconds at 18 seconds

14. The example in which nobody
bids.

15. iPhone 20 seconds auction
update update update update update
Here is the example in wich nobody bids.
Timer goes to check for 2 seconds and then shows
0.0