After having seen a couple of months with the word Ajax buzzing everywhere, I believe it’s time to clear a few things out.

Ajax is a term coined by Jesse James Garrett at San Francisco-based company Adaptive Path in February 2005. It is commonly described as “asynchronous Javascript and XML”. I would rather say it’s a shorter way of writing “asynchronous JavaScript using XMLHttpRequest with CSS and DOM”.

In other words, it’s a combination of various technologies from every web developer’s toolbox. These items have been around for a while and they are certainly not new kids on the block.

Ajax in a bottle Ajax – now 10 percent more efficient than the competition.

XMLHttp was first introduced to the world as an ActiveX control in IE 5.0, allowing pages to send XML via the HTTP protocol. XMLHttpRequest was originally invented in 1998 to create a web-based version of Outlook, so it’s not exactly new.

It has taken a while for the industry to grasp the power of Ajax, and the foremost reason why it’s suddenly so hot right now is that we’ve started to do smarter web applications featuring rich user interfaces built on Ajax.

Google Maps is perhaps the most well-known Ajax application and definitely one of the things that started the hype.

Other popular examples are Gmail, Google suggest (as I wrote about last year), Flickr and Orkut.

However, there are a few problems as well and most of them are concerning accessibility. Ajax applications inevitably involve running complex JavaScript code on the client. This doesn’t cope very well with the back button of your browser, thus breaking one of the most frequently used functions.

Another well-known feature is displaying when the browser is working. With Ajax you will have to take care of that yourself (which some developers probably will forget or simply ignore to implement).

Considerations must also be made in regards to JavaScript engines. it will have to work on Rhino (Mozilla’s JavaScript engine), Internet Explorer’s engine and so on. You will get fatter clients, which will make the web application more vulnerable to lesser target machine specifications.

And last but not least, a tenth of web surfers don’t have JavaScript, so they will not be able to use your cool Ajax application.

There are a lot more things to consider with Ajax development, but enough of all this negative thinking. I think that Ajax is a very useful technique and we will see a lot more of it in the near future.


  • avatar
    28 Dec, 2005

    Thanks for your great site!

  • avatar
    07 Mar, 2006

    I really enjoy reading your articles. Keep up the great work.

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