I'm using the Prototype helper "periodically_call_remote" to add a new item to a list similar to how http://election.twitter.com works.
My question is, how do I make it so that periodically_call_remote will only add items that it hasn't already added? The remote action is querying the database for new records, but it pulls all records that have been created since the page was originally loaded not the last time the periodically_call_remote fired. So, it adds the same new items every time it is called.
I have a few ideas about how to make this work, but none of them seem ideal. I'm sure this is a pretty common problem, and someone has already solved this.
Any ideas? Links? Suggestions?