Opera brings AJAX to mobiles

Opera has announced a beta SDK for its mobile phone Web browser and UI package, called Opera Platform. The announcement, made in conjunction with the W3C's Mobile Web Initiative event, held on Tuesday in London, promises to make mobile applications much easier for developers to create, and also cheaper for the end user.

The Opera Platform was announced two years ago as an alternative to building phone front-ends using native APIs. The SDK allows you to build applications for mobile phones using Web technologies such as HTML, CSS and JavaScript, but have then installed locally on the phone. The Opera Platform also gives you access to native features on the phone that wouldn't otherwise be accessible from Web technologies, such as address books or the ability to send SMS messages. An extension to the DOM provides the access to the phone's facilities.

The Opera Platform needs to be incorporated into a phone's operating system by its manufacturer, so this SDK won't allow you to create applications for all phones, and may be at a disadvantage to other technologies such as J2ME, which is included in many new phones.

The use of AJAX in Web applications has increased greatly since the appearance of services like Google Maps. By only transferring XML-encoded data, rather than entire Web pages, AJAX applications can appear much more interactive.

"The full Web browser has proved itself as a central application on mobile phones and is today the main source for data traffic on mobile networks," said Timo Bruns, vice-president for mobile products at Opera Software in a statement. "With Opera Platform we are now building the foundation for the next generation of mobile services by enabling the easy, fast and cost-effective creation of compelling Web based mobile applications."

One aim of the Opera Platform and SDK is to reduce the amount of data transfer needed for an application to work. Since the HTML for the front-end is already stored on the phone, less data needs to be downloaded over the wireless link. A recent investigation by Builder UK sister site ZDNet UK showed that roaming data charges can be several times higher than standard rates, so reducing the bandwidth needed for applications would be welcome for international travellers.

The SDK can be downloaded for free from the Opera Web site.