Offline support obviously would allow applications to work even when disconnected, but if such a feature were architected in a way that built on existing browser caching features, it might also result in improved caching in general, leading to significant performance improvements even when the user is connected.
Why Is This Important?
This features is essential to fulfilling the promise of Ajax; ie, desktop-like user experiences using browser technologies. Web-based applications to date have required an Internet connection (often, a *fast* connection) to operate. Furthermore, limitations with the browser cache have prevented certain classes of high-end web applications from being feasible due to the amount of logic and data that needs to be downloaded with each execution.
What exists today?
Google Gears focuses on offline browser applications, particularly its LocalServer features. The LocalServer allows a web developer to provide a manifest file that lists the files that should be cached locally across sessions.
The Gears team is working with the HTML5 effort to standardize its work. See HTML offline features, particularly the section on the "application cache".
In this section, the contributors should express their opinions about this feature request, such as providing particular technical analysis or describing in prose why this feature is important (or not). It is recommended that each contributor create his own level-3 sub-section (e.g., === Jon Ferraiolo Comments ===).
It is OK for others to insert comments within other people's sections, but as a courtesy please make sure that it is clear which part of the section is original and which section are annotative comments. For example, perhaps annotative comments would be colorized (e.g., enclosed by <span style="color:red">JON: Here is what I think about what you are saying.</span>).
Jon Ferraiolo's comments
This is an important feature and future browsers should give this a high priority, probably working together within the HTML5 effort. However, I have a concern with the latest draft of the HTML5 offline features. It looks more complicated than similar features in Gears. Why? Maybe there are good reasons why more complexity is necessary, but in general, the more complicated the spec, the more difficult it is for the industry to adopt it. Also, whenever I see a spec with a fallback feature, a red flag always goes up that the spec is going too far and trying too hard.
Nicole Tedesco's comments: implement a generalized resource archiving solution
(From NicoleTedesco) A generalized resource bundling solution (images, sound files, XML and even other HTML pages) can provide offline support for scripting, while also minimizing HTTP connection and overall bandwidth consumption. For details, see my comments in the Ajax Toolkit Caching discussion.
Phase I Voting - Vote for Your Top 5 Features
NOTE: PHASE I VOTING IS NOW OPEN. (2008-04-01) We have now changed the voting procedure. Instead of putting votes on each separate wiki page, we are asking people to cast their Phase I Votes on the following wiki page:
Phase II Voting
More about this later.