The Dojo open source Ajax development toolkit project has released a beta of its Dojo Offline Toolkit. 

Dojo Offline allows developers to quickly and easily equip their Ajax services with the ability to run without an internet connection and synchronise data when the connection is re-established.

The technology essentially allows online services to operate at all times, eliminating a major barrier for online applications.

Users of online text editors, for instance, will be able to open the application and edit their documents, regardless of their network status.

Similarly, an online email client such as Gmail or Hotmail could operate in an offline mode, allowing users to read messages and prepare new emails that are sent as soon as a network connection is established.

Dojo Offline stores user data and the actual application into a local cache that is synchronised whenever a network connection is detected.

It requires users to install a 300KB runtime engine and bundles a special JavaScript library with the application's code. The runtime engine will be automatically downloaded when the user clicks a link.

The application is accessed through a regular hyperlink that can be stored in the browser favourites, as an item in the start menu or on the system's desktop. The current beta works on Windows and Mac OS X systems.

The functionality of the Dojo tool is similar to that of Adobe's Apollo platform. Currently in the alpha testing stage, Apollo is the codename for a cross-operating system application runtime. It too relies on a runtime engine of 6MB (Windows) or 8MB (Mac OS X).