One of the things I missed when switching from Prototype to jQuery was the former’s Ajax.PeriodicalUpdater function. It is used to provide a ‘decay’ mechanism for ajax calls, making them less and less frequent if the retrieved content doesn’t change inbetween calls.

It can be a seriously useful piece of functionality. I took a chatroom that was polling every second and using an entire CPU core (50% usage!) and reduced it to 2-3% using this method. There were also errors retrieving content because sometimes the responses would take longer than a second to come back!

The problem is, there really isn’t a similar piece of functionality in jQuery.

So here it is! The script checks the returned data against previously received data, and increases the time between calls if it hasn’t changed.

I’d be interested in your comments. Would it be useful to turn this into a plugin?

View the demonstration here.

Steve Reynolds recently wrote a blog post showing how to access the twitter search API using PHP, cURL, and JQuery.

Steve used JQuery to post to a page on his server, which then cURLed in search results for a given term. This approach is often necessary to get avoid the issue of cross domain ajax calls.

While this approach works well, there’s an even easier way to go about it – $.getJSON!

There are two main advantages to this approach:

• Server side technology isn’t an issue. You don’t have to rely on PHP, cURL, firewalls, anything like that. It will even work on a static HTML page!
• All the work is done on the client’s browser – saving precious bandwidth! This could be important on busy sites.

I’ve knocked up a quick-and-dirty demonstration of this concept. If a name doesn’t already exist for this methodology, my vote goes for JAJA (Javascript and JSON, asynchronous!)

View the demonstration here!