Ajax (programming)

AJAX (sometimes spelled "Ajax") stands for Asynchronous JavaScript and XML. It is a technique used to make webpages faster to use. If they are programmed with AJAX, they seem to react faster. They only send small pieces of information to the web server. That way, the whole web page does not need to reload, only small parts of it.

Good things
There is a clear separation between what the page shows (its content), how it looks (its style), and what it does (its function). Programmers that change what the page does do not need to concern themselves with how the page looks.
Pages done with Ajax only load small pieces of information from the server. Most of the time, they execute code on the client. This makes the program load first so it can respond faster.
Ajax can be used to read XML or JSON, among other file formats.

Problems
There are also some problems with Ajax. These are among other things:
It uses JavaScript. Some people have JavaScript disabled.
Because it does not reload the full page, it breaks the history function of the Web browser. The Back button does not work any more.
If the network is slow (there is a high latency), this becomes more obvious when the whole page needs to be reloaded. Users might not expect these delays.
Some web browsers do not support Ajax well, if at all.

References

Category:Web software
Category:JavaScript