How to detect if a user leaves a page in PHP

Question

There is this function which i want to execute in case the user leaves a particular page. This function will basically change all of the data within a certain column in my d

Answer 1

With 100% reliability, no, it's not possible. Since leaving a particular page is a client-side operation, you have 0 control over what the client does. You can register an onbeforeunload handler via Javascript and hope that the client browser supports it. But again, support for this isn't universal.