In order for our programs to be useful, they usually depend on input from the user or other functions. By scaffolding our programs to be flexible, we also need to keep in mind the idea of scope: when and where we can use a function or variable. We also took a look at how objects can be used to store data efficiently for retrieval.
Let's not forget closures, the seemingly complicated concept that is, in practice, just a way of describing scope.
In the next chapter, we'll explore the frontend more as we get into using the Document Object Model (DOM) and manipulating information on the page instead of only interacting with alerts and the console.
