More and more people have been turning to Java and Ajax for scripts to make the functions they require run faster and take up less server time. By using these you have less call on the server, and this means you have a faster response time. Faster response time means the visitor is less likely to get bored waiting for the website to open so he will at least give you the chance to attract his or her attention with the headlines or the photographs.
Because of the need to use Ajax and Java, which are really the same thing but with XML added to it. The need to learn a little about it has never been more important.
Luckily, there are several sites that have information and tutorials for you.
The first of these is IBM, where you will find developer works for Ajax. You will find several tutorials here all of which are in-depth. These cover ground probably far beyond basic needs but very interesting. The one that I like was building a chat system, and I intend to look more fully into this.
Next to offer help is the Mozilla Org. This probably would be a good place to start. There is a guide here which you can use to learn the basics. I would download all the guides and learn as much as possible here. This will give you a good grounding on which to build your knowledge.
There is an Ajax community which is called Ajax Today, which gives out very interesting information about things like online classes and podcasts which you can sign up for. You can usually learn about various tutorials here, and if you wish can sign up for the RSS feed.
A repository of information on Ajax can be found at Ajax.solutoire.
An Ajax site called SitePoint gives useful information, which has been provided by pros and in addition, has a tutorial area where you can learn by example, and it is very informative.