A callback function is a function passed as an argument to another function, and it is executed after the completion of that function. Callbacks are widely used in asynchronous JavaScript.

This example shows how to pass a function as a parameter and call it after an action.

Callback functions are commonly used with asynchronous methods like setTimeout().

This shows how to execute a callback function after completing a task inside another function.

You can also use anonymous functions as callbacks without naming them separately.