Learn how to create a callback function in JavaScript and use it for various purposes, such as asynchronous programming, modularity, flexibility, and custom events.

This lab describes some more advanced concepts related to JavaScript functions. Be sure to take time to experiment or read up on a concept if you're not comfortable with the idea before moving on. If ...

Interestingly, any variables, functions, Arrays, etc. that are defined inside of the function expression's body can't be seen outside of the IIFE. To see this, check the value of baseNumber in the ...