AJAX POWER

Web developers were rudely awakened when Google introduced its Maps service. All of a sudden users could move maps dynamically, as though the application were running as a local GUI rather than in a browser. All of a sudden, time-consuming client-server round trips were hardly noticeable, since the current page didn’t need to be reloaded in order to reflect state changes in the application. Today, Ajax applications are sprouting all over the web. The beta release of Yahoo! Webmail, for example, looks very much like a desktop application; you have to take a very close look to see that your web browser is running the show. AJAX (Asynchronous JavaScript and XML) is based on dynamic HTML and client-side JavaScript. The XMLHttpRequest object, originally added by Microsoft and flying under the radar until Google helped it to fame, allows a JavaScript script downloaded from a website to exchange data asynchronously with the web server. It then dynamically smuggles this data into the HTML page, meaning that only minor changes need to take place on the page.