The ninth beta version of Firefox, due imminently, is set to get support for a standard called IndexedDB that provides a database interface useful for offline data storage and other tasks needing information on a browser's computer.

"IndexedDB allows Web apps to store large amounts of data on your local system (with your explicit permission, of course) for fast offline retrieval at a later time. We're hoping that Web mail, TV listings, and online purchase history will one day be as convenient to access offline as they are online," Ben Turner, who develops IndexedDB for Mozilla's browser, said yesterday in a blog post.

Firefox 4 beta 9 has been built, is being tested, and should become available soon. After that Mozilla presently plans to ship a 10th beta, release candidates, and a final Firefox 4 version in February.

One of the primary uses of IndexedDB is offline access to data used by Web applications. Google has offered such access to Gmail and Google Docs, for example, using a now-discontinued technology called Gears' it's likely the promised re-emergence of that technology in early 2011 will use IndexedDB.

Mozilla and Microsoft backed IndexedDB, which originated with an Oracle engineer, after raising concerns about a rival technology called Web SQL. Although Web SQL is built into Apple's Safari, Google's Chrome, and Opera (and Gears used the same approach), the World Wide Web Consortium (W3C) dropped Web SQL standardization work. Even though the SQL technology for database interaction is well known among many programmers, Web SQL standardization was hampered by the fact that its implementation was tied to a specific program, SQLite, not to a standard interface.

Google is building IndexedDB support into Chrome, and Microsoft looks likely to follow suit once the standard settles down. Currently Microsoft offers an experimental IE extension for developers.