JavaScript Variables

In JavaScript, variables are used to store data values. You can declare a variable using the var, let, or const keywords.

Declaring Variables

        
        // Using var
        var name = "John";
        
        // Using let
        let age = 30;
        
        // Using const
        const pi = 3.14;
        
    

Variable Naming Rules

• Variable names must begin with a letter, underscore (_), or dollar sign ($).
• Subsequent characters can also include digits (0-9).
• Variable names are case-sensitive (e.g., myVar and myvar are different).
• Reserved words (like JavaScript keywords) cannot be used as variable names.

Example

        
        var firstName = "Alice";
        let lastName = "Smith";
        const birthYear = 1990;

        console.log(firstName + " " + lastName + " was born in " + birthYear);
        
    

This code declares three variables and logs a message to the console.

Open the browser console (F12) to see the output of the example code.