How to How to dynamically update a counter that show numbers of received messages from a data base?

How to How to dynamically update a counter that show numbers of received messages from a data base?

Hi, 

I use PHP and I get the numbers of messages received by an user query a MySQL database and show it in a web page, I would like to update and refresh automatically the numbers of received messages without that the user has to use the refresh button.

How can I do it?, sorry, I am not used to use jquery.

Any example would be appreciated.

Thanks a lot

Francisco