How to make php alerts?

Question

PHP

Hello, CRM is being created. there is a manager and an accountant, orders are loaded by AJAX, if the manager sent documents to the accountant, then a notification flashes under the order, BUT only after the page is refreshed.
QUESTION: how to make an alert without refreshing the page, i.e. for example, how do notifications pop up in social networks and add sound?

Answer 1

If you do not plan a large load, then with web sockets, long pooling you can not bother, on the server side write a function that will check for changes, on the server side ajax request to this function with a cyclic call