How does Yahoo Mail make the back button traverse through previous clicks in their UI?

Question

Try the following case:

1. Log on to Yahoo Mail.
2. Click Inbox.
3. Click Drafts.
4. Click Sent.
5. Click Spam.
6. Click Trash.
7. Observe the browser's back history menu -- these different "pages" are not listed.
8. Now click back button multiple times-- the browser cycles through each of previously clicked "pages". (Note that "Forward" button is not available though...)

Finally, click logout. Now click back button .. none of the "pages" are in cache.

How does Yahoo do this? It seems like they are manipulating the use of the Back button.

Would appreciate an analysis of this since I would like to implement similar functionality.

Answer 1

They probably use their own Browser History Manager (the source is on github)