Ajax (Asynchronous Javascript And XML), pronounced ay-jax, is a web development technique using Javascript and HTTP requests to create more interactive web applications. Ajax allows web applications to retrieve small amounts of data from files or databases on the server without reloading the whole page.

Ajax Technologies

Ajax isn't actually a programming language in itself. Rather, Ajax makes use of a few preexistent technologies.

• Javascript's XMLHttpRequest object is the foundation of Ajax. This object allows Javascript to trade information with a web server without the need for reloading the page.

• XML is the format Ajax sometimes uses to transfer data between the client (user) and the server, however all formats are supported, including plain text and HTML.

• X/HTML and CSS is used for the styling and markup of dynamic content on the page.

• DOM, usually Javascript, is used to dynamically present and interact with the information given.

History

The term Ajax was coined in February 2005 by Jesse James Garrett while making a proposal to a client. However, similar technologies such as Remote Scripting (MSRS) by Microsoft were being developed dating back to 1998.

Ajax wasn't the first attempt at eliminating the need for total page refreshes. Introduced in Internet Explorer 3 in 1996, IFRAMES allowed for a portion of the content (ie the navigation) to remain loaded and only request new data within the dynamic frame. This technique is seldom used o the most modern websites.

Google's Use of Ajax

Ajax was made popular in 2005 with Google's release of Google Suggest which makes use of the technology. Google suggest working by analyzing the text you type in the search box before you're actually finished typing and making suggestions on search terms from the text you entered. For example, when I type in "Webma" it suggests Webmail, but when I continue to type "Webmaste" it suggests Webmaster. When I type "Webmaster T" it suggests Webmaster Tools, what I was originally searching for. All these suggestions are made without ever actually reloading the page.

One of the main advantages of Ajax is giving the ability to web developers to create web applications that behave similarly to local applications installed on your computer. For example, many people use Microsoft Outlook for email. If Outlooks is open and you receive an email, your inbox is automatically updated and the new email is displayed. Gmail (Google Email) tried to emulate this by checking for new mail when Gmail is open in your browser and automatically updating your inbox without any need to refresh the page.

DN Lodge's Use of Ajax 

Indeed, DN Lodge does make use of Ajax.  The prime example would be in the comment submissions below.  When you submit a comment, no page refresh is required.  Instead, you immediately see your comment or the moderation queue notice.  In the forums, quick replies are posted without page refreshes. 

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