AJAX library offers techniques for server-browser interaction
Pat Xin
Issue date: 6/9/06 Section: Sci-Tech
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What is AJAX? AJAX stands for Asynchronous JavaScript and XML. It is more a marketing term than a technical one, as the technology behind it does not have to be asynchronous, and often doesn't even use XML. In simple terms, AJAX is an approach to rendering Web pages that improves a Web site's appeal and usability. It enhances user interaction by targeting updates from the server to specific areas of a Web page. It allows information to be changed without long delays or frustrating page refreshes.
Although the technology is not new, its application is currently gaining momentum with Web developers. It used to be easy to distinguish the difference between pre-AJAX Web applications and common desktop applications. Such differences include graphical interface distinctions, low response times and page refreshing. As technology has improved, that line of distinction has slowing been fading. Although this presents some very exciting possibilities, it also presents some challenges.
AJAX was first devised in 1998 by Microsoft for their Web-based Outlook interface. Now, years later, it's supported by most common Web browsers. Although it was an Microsoft idea, it was popularized by Google in its stunning interface for Google Maps and the excellent usability of Gmail.
The AJAX that developers have come to know and love is all about better user experiences with server-browser communication and updates without the need or hassle of refreshing the entire page. This is great for updating parts of the screen in response to users in a very interactive and desktop-esque sort of way.
In basic AJAX, the browser makes the requests - that's where the problem is. Web servers can't easily contact Web browsers.
Hindrances such as firewalls can get in the way of the communication between the server and browser; even when they don't, browsers only listen for answers to questions they've asked the server. What if you want to build a highly interactive application that adds updates to your page as soon as someone halfway around the world updates theirs? What if you are in a content management system interface and you want to check out some content, but you find that a colleague has it checked out and has been editing for three minutes, and the page you are looking at hasn't been updated since then? Maybe you are an writer writing a manuscript for a book that is being shared between multiple users, and your editor makes some technical changes to certain paragraphs or passages. How can the Web server get the message through to the browser without having to wait for the question?
Although the technology is not new, its application is currently gaining momentum with Web developers. It used to be easy to distinguish the difference between pre-AJAX Web applications and common desktop applications. Such differences include graphical interface distinctions, low response times and page refreshing. As technology has improved, that line of distinction has slowing been fading. Although this presents some very exciting possibilities, it also presents some challenges.
AJAX was first devised in 1998 by Microsoft for their Web-based Outlook interface. Now, years later, it's supported by most common Web browsers. Although it was an Microsoft idea, it was popularized by Google in its stunning interface for Google Maps and the excellent usability of Gmail.
The AJAX that developers have come to know and love is all about better user experiences with server-browser communication and updates without the need or hassle of refreshing the entire page. This is great for updating parts of the screen in response to users in a very interactive and desktop-esque sort of way.
In basic AJAX, the browser makes the requests - that's where the problem is. Web servers can't easily contact Web browsers.
Hindrances such as firewalls can get in the way of the communication between the server and browser; even when they don't, browsers only listen for answers to questions they've asked the server. What if you want to build a highly interactive application that adds updates to your page as soon as someone halfway around the world updates theirs? What if you are in a content management system interface and you want to check out some content, but you find that a colleague has it checked out and has been editing for three minutes, and the page you are looking at hasn't been updated since then? Maybe you are an writer writing a manuscript for a book that is being shared between multiple users, and your editor makes some technical changes to certain paragraphs or passages. How can the Web server get the message through to the browser without having to wait for the question?
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