how to update feeds dynamically

[chalasesha]

i am developing a social networking site as my project in college.
i have a doubt on php and mysql..

""" I TWITTER OR FACEBOOK OR IN GMAIL WHEN THERE IS NO ACTION FROM USER(BROWSER) THAT IS, THE USER LOGS IN AND STAY STILL(NOT RELOADING THE PAGE). HOW CAN WE UPDATE THE FEEDS OR MESSAGES DYNAMICALLY AS OHTER USERS SENDING MAILS OR DOING SOME ACTIVITY IN THEIR PROFILES. """""

I WANNA KNOW HOW CAN WE SHOW SOME MESSAGE FROM DATABASE TO THE CLIENT WITHOUT ANY BROWSER ACTION FROM USER. JUST LIKE FACEBOOK FEEDS AND TWEETS..

WAITING FOR REPLY

[pritaeas]

You can use AJAX (Javascript) to periodically check the server for new messages. It cannot be done solely with PHP/MySQL.

[chalasesha]

if you use ajax to do a function from the server there should occur an event from the client browser. how can we update feeds dynamically without an action from user.
i mean user logs in and stays still.

[pritaeas]

Javascript has a setTimeout() function that works like a timer. Every time it fires you can do something, whether the user is active or not.

[chalasesha]

thank you very much... i love you!