I had to do a very quick survey of what is possible to do with Google Gears. And frankly, it's exactly what I was looking for in a very special case: a simple ajax application, that people are using while connected to the internet most of the time but that should still be  usable for its simplest usage of inputing information into the system most of the day, while the internet connection of the user is down.

Google Gears is then perfect, first to cache information necessary to make an easy task of inputing the informations, second to store the entered information waiting for the server to be available. It's still a plugin that the user has to install, but it's available on various browsers and different OSes.

The final question is then : what framework should I use to build the Ajax application ?

Using the Google Web Toolkit and its ability to compile a java application to its html & javascript equivalent is very tempting for someone used to Java programming and Java IDEs. I have still to dig in, but its extensibility if the provided widgets are not sufficient is also interesting.

Now, Dojo is also integrating Google Gears and its usage with php applications (there is a partnership with the zend framework) could be quite interesting. Now, I have to look into other frameworks to see how easy it would be to use them together with gears.

In the end, the title of this post translates to : java or php ?