I was going to post this as a question, then as a problem, but now I think it should just be sharing my experience.

On my page I have a jQuery modal dialog. It contains a checkbox associated with a product being shown in the dialog. Checking the checkbox is supposed to post the product's title to the server (using $.post). During my tests, I opened the dialog for different products, checked the checkbox and quickly pressed Esc key to close the dialog and move on to another product. What I've noticed is that if current product title to be posted is different from one sent just prior to it, things get posted quickly and without a loss. However, if I am sending the same data as what was sent with a previous request, this data doesn't make it to the server if I do this quickly -- I consistently lose data. But if I allow a couple of seconds to pass before pressing Esc key, the data (duplicate data) gets delivered fine.

This happens only in Firefox (I've tried this in v. 3.6). IE 8 and Chrome 4.0.249.89 beta (38071) (it was supposed to be 5.x, though) behave as expected -- post data without delay or concern with duplicate data.

In summary: if posting what seems like duplicate data in Firefox, posting is delayed, and pressing Esc too soon can abort posting.