How does WordPress back up and save a post when disconnected?

Question

Has anyone encountered this when saving a WordPress post/page?

"Connection lost. Saving has been disabled until you're reconnected. We're backing up this post in your browser, just in case."

I'm interested in what kind of tools WordPress uses to cache data. What did they mean by: saving into XML in browser cache? Raw data? Or another technology?

Can all browsers do that?

I've searched online for answers but have not found anything helpful.

Answer 1

I'm interest what kind of tech wp use for backup the data into browser, specially using php.

None. PHP runs server-side. It doesn't run in the browser.

What you're looking for is HTML5 Local Storage. You can store strings, or even put stuff into a small database.

http://www.html5rocks.com/en/features/storage

This is well supported by many browsers: http://caniuse.com/#search=localstorage