2009/6/23 Aamchi <[email protected]> > > Hi, > > I was wondering if Ajax.PeriodicalUpdater can detect if content has > changed since the last update and if so trigger an event. > > So for example I have a scoreboard which fetches data every 5 seconds > and displays this. I would be cool if there could be some kind of > notification if content had changed. I know that the new content is > stores in responseText but how can I compare it to the previous > content... > > Thanks, > Aman > > > > Personally, I would do this server side. Assuming you get the data in some sort of structure before either rending some HTML and sending it or just sending it JSON'd, then you should be able to build a hash of the data.
See [1] for info on Hash Functions. So. If you sent the hash value in a X-JSON header along with an onSuccess() callback, you can extract the hash from the second param to the onSuccess and compare this with the previously retrieved hash to indicate you've got changed data. See [2] for details about PeriodicalUpdater update notification and [3] for the parameters to common callbacks. Regards, Richard. [1] http://en.wikipedia.org/wiki/Hash_function [2] http://www.prototypejs.org/api/ajax/periodicalUpdater <http://www.prototypejs.org/api/ajax/periodicalUpdater>[3] http://www.prototypejs.org/api/ajax/options <http://www.prototypejs.org/api/ajax/options> -- ----- Richard Quadling Zend Certified Engineer : http://zend.com/zce.php?c=ZEND002498&r=213474731 "Standing on the shoulders of some very clever giants!" --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Prototype & script.aculo.us" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/prototype-scriptaculous?hl=en -~----------~----~----~----~------~----~------~--~---
