A callback function is a function that is passed as an argument to another function and is expected to be called back (executed) by that function as part of its job). Callbacks are used in situations where a function needs to wait for a task to complete before continuing its execution. The callback function is executed after the task is completed, and its purpose is to execute code in response to an event.
In JavaScript, callbacks are often used in asynchronous functions, where one function has to wait for another function (like waiting for a file to load) . When a function is passed as an argument to another function, it is important to remember not to use parentheses.
Callbacks have a wide variety of uses, including error signaling, event handling, and asynchronous programming). They are also used to program applications in windowing systems, where the application supplies a specific custom callback function for the operating system to call in response to events like mouse clicks or key presses).
