If you've spent time using Google Docs & Spreadsheets, you're familiar with the service's great features. You are also familiar with a semiregular 'Disconnected' error that forces you to toss out your recent changes or switch to a read-only version of your document when your browser loses touch with the Google service. That's the Achilles' heel of today's rich and promising desktop-like Web apps: They require a hiccup-free Internet connection. If anything interrupts that link, you can lose sync--and your data. At the very least, your info is out of reach.
But developers are working to get around that drawback, using intelligent caching to build offline functionality into their Web applications and browsers.
A new desktop version of Zimbra's browser-based productivity suite can cache your e-mail and calendar data, untethering Zimbra's app from an Internet connection. And a still-in-the-works offering from Scrybe promises a Web app with calendaring and other features that will continue to function even when you activate your browser's "work offline" mode.
Mozilla.org is taking an even broader approach, building offline caching into Firefox 3, due out in beta this summer. Any Web site will be able to take advantage of the feature, though online apps will need to be updated to make use of it.
While caching can free Web apps from the need for a Web connection, another emerging technology aims to free them from the browser. With promises reminiscent of Sun's Java, Adobe says that its new Apollo platform, available as an alpha release, allows Web developers to write applications using online programming tools like Flash and Ajax that run on the desktop without a
