JavaScript Variables – Simple Example with Result
A variable in JavaScript is used to store data such as numbers, text, or other values.
Syntax
var variableName = value;
or
let variableName = value;
or
const variableName = value;
Example 1: Using var
<!DOCTYPE html>
<html>
<head>
<title>JavaScript Variable Example</title>
</head>
<body>
<h2>JavaScript Variable Example</h2>
<p id="result"></p>
<script>
var studentName = "Rahul";
var age = 21;
document.getElementById("result").innerHTML =
"Student Name: " + studentName + "<br>" +
"Age: " + age;
</script>
</body>
</html>
Output
Student Name: Rahul
Age: 21
Example 2: Adding Two Numbers
<!DOCTYPE html>
<html>
<head>
<title>Addition Example</title>
</head>
<body>
<h2>Addition of Two Numbers</h2>
<p id="demo"></p>
<script>
var num1 = 25;
var num2 = 15;
var sum = num1 + num2;
document.getElementById("demo").innerHTML =
"Number 1 = " + num1 + "<br>" +
"Number 2 = " + num2 + "<br>" +
"Sum = " + sum;
</script>
</body>
</html>
Output
Number 1 = 25
Number 2 = 15
Sum = 40
Example 3: Using let
<!DOCTYPE html>
<html>
<body>
<p id="demo"></p>
<script>
let city = "Nagpur";
let state = "Maharashtra";
document.getElementById("demo").innerHTML =
"City: " + city + "<br>" +
"State: " + state;
</script>
</body>
</html>
Output
City: Nagpur
State: Maharashtra
Example 4: Using const
<!DOCTYPE html>
<html>
<body>
<p id="demo"></p>
<script>
const PI = 3.14159;
const radius = 5;
let area = PI * radius * radius;
document.getElementById("demo").innerHTML =
"Radius = " + radius + "<br>" +
"Area = " + area;
</script>
</body>
</html>
Output
Radius = 5
Area = 78.53975
Difference Between var, let, and const
| Keyword | Can be Reassigned | Can be Redeclared | Scope |
|---|---|---|---|
var | ✅ Yes | ✅ Yes | Function Scope |
let | ✅ Yes | ❌ No | Block Scope |
const | ❌ No | ❌ No | Block Scope |
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