@phpdeveloper.org
Jim Plush has an interesting post today (complete with a video) about a project he's worked up for sending messages to remote devices via a web connetion and a JSON encoded message.
I have my PDA resting on my laptop and on my laptop I have firefox open with a local PHP page. The PHP page has a couple checkboxes that when clicked and the submit button pressed will actually open up a socket connection to the IP address I specified in the text field above. The script then sends a JSON encoded event string of data. That string gets read in by a custom minimo/firefox extension I wrote that listens on a particular port for incoming connections, reads in any data sent then forwards that on to user land javascript. By user land javascript I mean javascript written on a regular webpage, not in the extension itself.
The video linked to in the post shows more clearly how this functionality works, and also includes a bit more detail on the whole process, including a graphical representation of how the entire process works. Ajax wasn't actually used to send the message in this particular application - it's all just made with regular sockets.