Introduction to AJAX
Using AJAX can be a bit cumbersome, because the various browsers have different implementations to support AJAX. Normally this would force you to write code to respond differently, depending on the browser, but fortunately, jQuery has done this for us, which allows us to write AJAX functionality with as little as a single line of code.
You should be aware of the fact that thre are both advantages and disadvantages to using AJAX on your page though, which means that you should always consider carefully before deciding to use it instead of doing a regular postback to the server. Here's a summary:
- Your page will be more pleasant to use, when you can update parts of it without a refresh, which causes the browser to flicker and the statusbar to run.
- Because you only load the data you need to update the page, instead of refreshing the entire page, you save bandwidth.
- For the same reason, a specific state can't be bookmarked by the user.
- Data loaded through AJAX won't be indexed by any of the major search engines.
The first two items on the list may be circumvented though, typically through the use of an iframe and reading and writing data from the part of the URL after the # character.
In the following chapters, you will learn how to use various AJAX related functions of jQuery.