How To Learn Ajax
Submitted by: TigerEye
The programming language Ajax has become popular because it makes a regular html document dynamic. Here we will talk about the language that uses asynchronous javaScript and XML to create dynamic web pages.
The first step is to learn javascript and xml. They are not the focus of this article. If you do not know javascript or xml you will need to do that before proceeding with ajax the programming language. Ajax begins by using a XMLHttpRequest to call actions from the server. Clicking on an active link or such will be enough to initiate this action. If you take a look at the format of "XMLHttpRequest" you will be led to believe that ajax always uses a bit of xml to function. This is not always true.
The browser being used will be sensitive to either using the tag "XMLHttpRequest" ( for Firefox ) or "ActiveXObject" ( for Internet Explorer ). If we take a look online at google, and use the search term; "for learning ajax" ( just like it is written here ) we come up with examples on the first page that are not all that basic. Nevertheless they lead to pages where you can buy your own books to learn ajax. If you are a book learner, this may be the best way, instead of reading pages like this one. One book that is recommended is called; "Ajax Patterns and Best Practices" and is written by Christian Goss. It is published by Apress Books.
The thing to remember is that ajax is going to change the layout of the page. You will also need to learn how to leave the width of the page unchanged if information will be taking up a significant amount of pixels on the page horizontally. If the size of the page will be changed vertically it is easier to manage.
Some sites that give out basic information on ajax will tell you that the typical life cycle of ajax comprises about three major events with the third being the more complicated one. The first step is of course the arrival of the visitor to the page or document. This causes the second event which is called initialization ( low level formatting of information ). The third event is the loop. The event loop can consist of a browser event such as a click of a mouse on the page. This sends a request to the server and it is processed. The server responds and the page itself is used to call the change. The last thing that happens is that the browser is updated.
To learn ajax you will need to think in terms of the above scenario. You are usually going to be calling information from a server to change the page your visitor is looking at. In times past you had to wait for the whole page to reload for the information on the page to change. That is done away with using ajax. Think along these lines and ajax will come alive to you.
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1: How To Learn AjaxWord Count: 513 Date: Wed, 30 Dec 2009 Time: 3:21 AM
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