JavaScript has had the XMLHttpRequest

If you hang out with designers and developers at all, then you’ve probably heard the term “Ajax” by now. It’s the official buzzword of Web 2.0. But it’s also an extremely useful web development technique.

In the course of this tutorial, we’re going to look at what Ajax can do. Then we’ll use a JavaScript class to simplify your first steps toward the ultimate in speedy user interactivity.

First, what is Ajax? It stands for Asynchronous JavaScript And XML. In simple speak, Ajax allows us to use JavaScript to grab an XML file (or any other text) without reloading the whole web page.

Ajax has been used for a lot of things, but it is most impressive when many small updates are needed in a short period. Think streaming stock quotes or draggable maps.

In our example, we’ll use a pair of dropdown menu boxes (SELECT tags in HTML). A selection in the first box affects our list of choices in the second box. It’s not exactly cutting edge (Thau did something similarusing JavaScript), but it’s a proof of concept.