JavaScript Loops Explained with Examples

Loops in JavaScript are used to repeat a block of code multiple times—until a certain condition is false. They are essential for iterating over arrays, objects, and performing repetitive tasks.

1. for Loop – Best for known iteration count

Syntax:

for (initialization; condition; increment) {
  // code block
}

Example:

for (let i = 1; i <= 3; i++) {
  console.log("Count: " + i);
}

Output

2. while Loop – Runs while the condition is true

Example:

let i = 1;
while (i <= 3) {
  console.log("While loop count: " + i);
  i++;
}

Output

3. do...while Loop – Runs at least once, then checks condition

Example:

let i = 1;
do {
  console.log("Do While count: " + i);
  i++;
} while (i <= 3);

Output

4. for...of Loop – Loops over iterables like arrays

Example:

let fruits = ["Apple", "Banana", "Cherry"];

for (let fruit of fruits) {
  console.log(fruit);
}

Output

5. for...in Loop – Loops over object keys

Example:

let person = { name: "Alice", age: 25 };

for (let key in person) {
  console.log(key + ": " + person[key]);
}

Output

Summary Table – JavaScript Loops