JavaScript how to make callback function

Javascript callback functions allow easy reuse of code. Learn how to create one with an example.

Creating a Callback Function in JavaScript

A callback function is a function that is passed as an argument to another function and is executed after some kind of event.

In JavaScript, we can pass functions as arguments to other functions. This is called a “callback” function because it is called after the event has occurred. For example, you can create a function that will be called after a button is clicked:

// Create a function that will be called after a button is clicked
function myCallback() {
  alert('Button was clicked!');
}

// Create a button
var btn = document.createElement("BUTTON");

// Add an event listener to the button, that calls myCallback() when the button is clicked
btn.addEventListener("click", myCallback);

In the above example, the myCallback() function will be called whenever the button is clicked. This is a simple example of how to use a callback function in JavaScript.

Another way to use callback functions is to pass them as arguments to other functions. For example, you can create a function that will be called after an array is sorted:

// Create an array of numbers
var numbers = [4, 2, 5, 1, 3];

// Create a function that will be called after the array is sorted
function myCallback(arr) {
  console.log(arr); // [1, 2, 3, 4, 5]
}

// Sort the array, and pass myCallback as an argument
numbers.sort(myCallback);

In the above example, the myCallback() function will be called after the numbers array is sorted. This is another example of how to use a callback function in JavaScript.

Callback functions can be used for many different tasks in JavaScript. They are a powerful and flexible way to handle events and can make your code much more organized and efficient.