PHP infinite loop to obtain data (or message) information

PHP infinite loop to get data (or message) information I php basically do not know much about, because the project needs, I need to write JSP instant chat system embedded in PHP.
The only question left now is how to obtain the data information in the framework (because the customer service may ask for the invitation chat information to pop up at any time, the cycle or message must be invalid ), I would like to ask if PHP has infinite loop acquisition and the interface won't be stuck in the main usage (or you can get data once every other period of time)

Reply to discussion (solution)

Jquery

OK, thank you. I just found a small example of jquery loop. it's pretty good. it should be usable.