Here is the thing: PHP is a server technology.In a typical client-server type of architecture, messages are"pulled" rather than "pushed". In other words the server does not "send" or "push" the messages out to its users. The users "request" or "pull" the messages from the server. In other words,you need a PHP script that publishes a message.That message can be whatever you want: a file,a database table record, etc. You then write client-side code to poll the server for new messages on a set interval.That client can be either a web browser,or an ad-hoc client coded in virtually any programming language.