Thanks, for your response. I'm not 100% sure if I understand correctly what you mean. If I get some data and generate a hash and write this to the JSON header and retrieve this when calling onSuccess, how will I still have the previous hash? From where will I get this? Won't the updated data cause the hash to be overwritten in the JSON header? Or do I have to send two hashes always and compare them?
On 23 Jun., 22:57, Richard Quadling <[email protected]> wrote: > 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 -~----------~----~----~----~------~----~------~--~---
