XHR: on success, on failure, pause an xhr and come back to it later:

?

Timer/Timeout:

Yes.

http://tapestry.apache.org/tapestry4.1/tapestry-contrib/componentreference/timeout.html

History/state (back button):

Kind of. The server is not aware of back button hits and therefore some synchronization issues arise. Hidden fields to maintain state will overcome this.

http://tapestry.apache.org/tapestry3/doc/DevelopersGuide/pages.stale-links.html

Off-line Storage:

Cookies are available as well as 'Save...' dialog box for saving files / values.

Interaction with the Desktop applications:

No.

Extensibility:

Very good, especially in the latest release. Includes suport for js frameworks (e.g. Prototype, dojo).

Animation:

Yes, via. javascript.

Number of Items that can be displayed in the interface without causing memory or computation problems.

?

Support for stateless messaging? -scalability:

Yes.

Usability? Bookmarking/Layout font-size changes:

Yes.

Browser Portability:

Very good.

Start Time? How big are the javascripts/swf files....

Should be relatively similar to regular HTML - small files for the client.

TESTING and Debugging tools. How can you test the GUI interface? GWTTestCase

Has support for both client-side and server-side debugging. Also has Eclipse IDE integration for development.

Will the generated HTML be portable and what happens when a new browser comes in?

Yes.

Remote Process Calls? Different from JSON and XML.

?

Batch XML Http Requests?

?