What are Javascript variables | JS variables 101

JavaScript variables are used to store data values. They are containers that hold values that can be used in your code.

Variables in JavaScript are declared using the var, let, or const keywords. Here’s a brief overview of each:

• var: Variables declared with var are function-scoped, meaning they are only accessible within the function in which they are declared.
• let: Variables declared with let are block-scoped, meaning they are only accessible within the block in which they are declared (e.g., within a loop or if statement).
• const: Variables declared with const are also block-scoped, but their value cannot be changed once it has been assigned.

Here’s an example of how you can declare and assign a value to a variable in JavaScript:


var myVariable = 'Hello, world!';


In this example, we’ve declared a variable called myVariable and assigned it the value 'Hello, world!'. We can then access this value later in our code by referencing the variable name.

Variables in JavaScript can store a variety of data types, including strings, numbers, booleans, arrays, objects, and functions. They can also be reassigned with new values as needed.

Understanding how to declare and use variables in JavaScript is a fundamental concept that is essential for writing effective and efficient code. By using variables, you can store and manipulate data within your scripts, making your code more dynamic and reusable.