Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

JavaScript

Posted by A S
A S
7,485 Points

Function and Parameter

The callback function is not declared earlier but it's related to the getUserName(callback) I am pretty confused about this snippet.

The callback is the biggest confusion here. Please help!

function getUserName(callback) {
  const name = prompt('What is your name?');
  callback(name);
}

function greeting(name) {
  alert('Hello, ' + name);
}

getUserName(greeting);

1 Answer

Reggie Williams
STAFF
Reggie Williams
Treehouse Teacher
Reggie Williams
Reggie Williams
Treehouse Teacher

Hey Arash Seyedi it looks like in this example callback is an parameter or place holder. getUserName is a function that calls another function and callback just shows how that function is called when it is passed in. In this example getUserName calls the greeting function