What David Heinemeier Hansson writes today links together the two latest posts I made here:
We’re currently polling every three seconds for every user active in a chat and while we’ll soon be able to regulate that between three and thirty seconds (depending on how active the chat is), it has certainly presented us with ’special needs’.
Exactly. As I wrote yesterday:
A second downside is that AJAX makes it really easy to write web pages that can hog a server much more than a traditional template processing step will ever be able to do. I can already see AJAX widgets constantly polling servers for updated data (news tickers, etc.) and possibly keeping server sockets tied for a long time, which is a usage pattern that most servers were not designed to cope well with.
So much for making the web run faster.
However, even with all this polling going on, Campfire is quite snappy and responsive. It’s really like IRC in a web browser, done right. I’m particularly intrigued by how they managed to have the browser window scrollbar scroll just the chat transcript and not the whole page. Brilliant! This is an application that really sets a new standard for web-based applications.
If you set layers to position fixed, they will not scroll away. They just probably did that for the surrounding interface and let the chat window be the main page that scrolls normally.
Possibly, but I saw some Javascript code related to scrollin in there. Moreover, you still have to take care of IE, which doesn’t support position:fixed.