AjaxLine

Introduction
This article mainly for people who wants to know what means this word. You may think that it’s some kind of washing powder or a football club :)… no today you think wrong…

Ajax
We may say that it’s Asynchronous JavaScript + XML as it was coined
by Jesse James Garrett of Adaptive Path. But it’s something more then just Asynchronous JavaScript + XML. To take a closer look at this technolodgy you must see famous in Ajax world Google's applications: Google Maps, Google Suggest and Gmail.

Body
What common in these web applications? – Yes they are very similar to our desktop applications. As we know in usual web site when we press link or choose some menu item all page posts to server… than it returns to our browser (it’s so slowly! we usually should wait more than 2 seconds!) but in our windows GUI apps we receive momentary response without any winking. And now we have web technology that can help us to build user interfaces very close to desktop GUI! Ajax provides user with really friendly interface without this disgusting postbacks!!!

Ajax elements
Let’s look closer to key Ajax elements
XMLHttpRequest object
The main tool for asynchronous manipulations. Allow us to retrieve and send data from and to server without postbacks in background.

JavaScript
Client scripting language that allows us to build Ajax apps. Very powerful language with great abilities.

Document Object Model (DOM)
Presents structure of web page as hierarchical tree. Allows us to modify page’s objects through JavaScript.

Cascading Style Sheets (CSS)
It’s set of visual properties of page’s objects that help us to build really friendly user Ajax interfaces.

Difficulties
Before this moment we talked only about advantages of using this technology. But there are some difficulties… As I said Ajax applications need lots of client JavaScript code and sometimes it can be really difficult to manage with all this heap of code… What is more JavaScript is not strong typed language like C#, Java it interpreted language so it’s very easy to make very stupid mistakes in a code and spent alot of time to find it.
To deal with it Ajax – programmer has to be familiar with such techniques and areas of knowledge as refactoring, OOP, design patterns, XML, regular expressions, JavaScript, XHTML, CSS and at least one server technology(PHP,ASP.NET, JSP, Perl ect.)
You see :) not short list of requirements but it is worth to know these.

Some Google's Ajax applications
http://maps.google.com
http://www.google.com/webhp?complete=1&hl=en
http://gmail.com

Copyright(c) 2006 Kigorw. special for http://ajaxline.com/