Ajax

Before we begin, this article is intended for those who require a basic understanding of Ajax. If you already know something about Ajax then this is probably not for you! OK, lets begin...

So what does Ajax stand for and what is it? Ajax stands for Asynchronous JavaScript and XML. It is a collection of technologies, none of which are new, but together allow dynamic interaction between users and a server without refreshing a web page and without the requirement of any plugins. The end result is similar to desktop applications. It requires a browser that supports javascript but different browsers support different aspects of Javascript. This complicates matters a little but, as web standards become more important, the powerful, non-compliant organisations may succumb to these standards and therefore these differences may disappear - we hope!

What is all the hype about?

Well Ajax allows you to interact with dynamic web sites without your page disappearing from the screen and a new one appearing again, the content of which is largely the same but just with minor data changes. Ajax, simply displays your results on the same page. Why is this good? If coded correctly it reduces bandwidth. Only the necessary data is transferred across and back to the server and not the whole page as is the case now. This means lower hosting costs and a faster user experience.

What can you do using Ajax? You could create an online chat system where messages can be sent and received all on the same screen without the requirement of plugins. The possibilities are endless. Google has already taken the lead and implemented this methodology into its search facility called Google Suggest. When you stop typing Google will search its vast database and, using its complex algorithms, will suggest various search terms for you - all in real time! Another impressive applicable use of Ajax is Google Maps. You can search the world, zoom in and out, move in different directions all without refreshing the page! One more example (and no its not from Google) is a real-time Amazon search facility created, not by Amazon, but by Francis Shanahan a senior software architect. Appropriately named Amazon Zuggest, you type and it searches Amazon, displaying the results without pressing any "submit" button.

Are there any disadvantages?

In a nutshell, yes - as would be expected. There are usability issues. Since there is no page refreshing when you press back on the browser you end up going back to the last loaded page in the traditional sense. Since the url or its parameters do not change in the address bar, how do you save your favourite pages? As mentioned earlier, not all browsers will work with ajax technology due to the requirement of Javascript. Also users may switch off the Javascript capability in their browsers which would cause the system to fail. Despite this Ajax is a new and exciting way of using a combination of old technologies that will at least increase end-user experience once small inconsistencies are ironed out or overcome.