Loops in JavaScript

In this tutorial, we will learn about different types of loops in JavaScript. We will cover the basics of for, while, and do-while loops.

What is a Loop

A loop is a control flow statement that allows code to be executed repeatedly based on a condition.

Loops

JavaScript supports three types of loops: for loops, while loops, and do-while loops.

For Loop

A for loop is used when the number of iterations is known before entering the loop. The syntax for the for loop is:

for (initialization; condition; increment) {
    // Code block to be executed
}

While Loop

A while loop is used when the number of iterations is not known beforehand. The syntax for the while loop is:

while (condition) {
    // Code block to be executed
}

Do-While Loop

A do-while loop is similar to a while loop, but it guarantees that the code block will be executed at least once. The syntax for the do-while loop is:

do {
    // Code block to be executed
} while (condition);

Example 1: Printing Numbers from 1 to 10 using For Loop

  1. Declare an integer variable i.
  2. Use a for loop to print numbers from 1 to 10.

JavaScript Program

for (let i = 1; i <= 10; i++) {
    console.log(i);
}

Output

1
2
3
4
5
6
7
8
9
10

Example 2: Printing Numbers from 1 to 5 using While Loop

  1. Declare an integer variable i and initialize it to 1.
  2. Use a while loop to print numbers from 1 to 5.

JavaScript Program

let i = 1;
while (i <= 5) {
    console.log(i);
    i++;
}

Output

1
2
3
4
5

Example 3: Printing Numbers from 1 to 3 using Do-While Loop

  1. Declare an integer variable i and initialize it to 1.
  2. Use a do-while loop to print numbers from 1 to 3.

JavaScript Program

let i = 1;
do {
    console.log(i);
    i++;
} while (i <= 3);

Output

1
2
3