Overview
In JavaScript, variables are used to store data that will be used in multiple places. This allows the data to be kept in one place for ease of change.
Variables can be declared using three different methods: var, let, and const. See the JavaScript resource on var vs. let vs. const to see how and when each should be used.
var
“var” is typically used when a value may change over time.
var x = 5;let
“let” is typically used when a value is restricted to the block { } of code where it is created.
let x = 5;const
“const” is typically used when a value CANNOT change over time.
const first_name = 'Johnny';JavaScript Notes:
- When using JavaScript, single or double quotation marks are acceptable and work identically to one another; choose whichever you prefer, and stay consistent
- JavaScript is a case-sensitive language; firstName is NOT the same as firstname
- Arrays count starting from zero NOT one; so item 1 is position [0], item 2 is position [1], and item 3 is position [2] … and so on
- JavaScript variables must begin with a letter, $, or _
- JavaScript variables are case sensitive (x is not the same as X)
We’d like to acknowledge that we learned a great deal of our coding from W3Schools and TutorialsPoint, borrowing heavily from their teaching process and excellent code examples. We highly recommend both sites to deepen your experience, and further your coding journey. We’re just hitting the basics here at 1SMARTchicken.