Essential JavaScript

Naming Variables

Different programming languages have different conventions for how to name variables.

In JavaScript we name variables using camel case. In camel case, all letters are lowercase unless we are starting a new word.

It's called camel case because the uppercase letters in the middle of the variable names look like the humps on a camel.

Using Camel Case

These are examples of how to take a descriptive name and turn it into camel case:

Original Descriptive Name Camel Case Variable Name
Value value
Input String inputString
Number 1 number1
Customer Age customerAge
Shopping Cart Item Count shoppingCartItemCount
User ID userID
Flight ETA flightETA
HTML Element HTMLElement


Functions and arguments follow this same rule. Always use camel case.

Your code won't break if you use another naming convention, but it will look out of place to an experienced developer. All of JavaScript's built-in functions use camel case. Keep variable names consistent and they will be easier to read.


Look at the code in the editor. The variables should all be in camel case to keep things consistent. Fix the code by converting all values to camel case.

Remember that strings are not variable names, so you don't need to change the string arguments.

Learning Goals

Code Editor