you should know that ajax work with web servers .when you work
with ajax ,you should connecting to a webserver and send your message.
then webserver send response to you.if you have not a web server in
your LAN ajax can not send and recive data.you can recive data from a
web server on WAN(Internet)with http://.test it... because in WAN a
web server is waiting for your request but in your Lan ...NO!
additionally if you have a web server in your LAN ,your web server
should be configure.at last test your firewall ,if you have one of
them.