Do I need ES6 features to follow these examples?

Most examples use core syntax supported by modern browsers. ES6 features are noted where used.

Can I modify and share these examples?

Yes. These are for learning—copy, tweak, and share your variations for practice.

Where should beginners start?

Begin with Hello World, variables, arithmetic, then progress to control flow, functions, strings, and arrays.

Math and Number Utilities

Practice math-focused snippets: factorials, prime checks, divisors, GCD/LCM, sums, and multiplication tables. Emphasis on efficient loops and clean utility functions useful for interviews and fundamentals.

Try JavaScript Compiler

JavaScript Program to Display Fibonacci Sequence Using Recursion

Recursive Fibonacci.

                          function fib(n){return n<2?n: fib(n-1)+fib(n-2);} console.log(Array.from({length:10},(_,i)=>fib(i)));
                        

Output

JavaScript Program to Find the Square Root

Compute square root using Math.sqrt.

const n=81; console.log(Math.sqrt(n));

Output

JavaScript Program to Check Prime Number

Check divisibility up to sqrt(n).

                          function isPrime(n){if(n<2)return false; for(let i=2;i*i<=n;i++){if(n%i===0)return false;} return true;} console.log(isPrime(29));
                        

Output

JavaScript Program to Print All Prime Numbers in an Interval

List primes in a range.

                          function isPrime(n){if(n<2)return false; for(let i=2;i*i<=n;i++){if(n%i===0)return false;} return true;} const out=[]; for(let n=10;n<=50;n++){if(isPrime(n))out.push(n);} console.log(out.join(", "));
                        

Output

JavaScript Program to Find the Factorial of a Number

Iterative factorial.

                          function fact(n){let f=1; for(let i=2;i<=n;i++){f*=i;} return f;} console.log(fact(5));
                        

Output

JavaScript Program to Display the Multiplication Table

Multiplication table for a number.

const n=5; for(let i=1;i<=10;i++){ console.log(n+" x "+i+" = "+(n*i)); }

Output

JavaScript Program to Print the Fibonacci Sequence

Generate the first N Fibonacci numbers.

                          function fib(n){const a=[0,1]; for(let i=2;i<n;i++){a[i]=a[i-1]+a[i-2];} return a.slice(0,n);} console.log(fib(10));
                        

Output

JavaScript Program to Check Armstrong Number

Check if sum of powered digits equals number.

                          function isArmstrong(n){const s=String(n); const p=s.length; let sum=0; for(const ch of s){sum+=Math.pow(Number(ch),p);} return sum===n;} console.log(isArmstrong(153));
                        

Output

JavaScript Program to Find Armstrong Number in an Interval

List Armstrong numbers in range.

                          function isA(n){const s=String(n); const p=s.length; let sum=0; for(const ch of s){sum+=Math.pow(Number(ch),p);} return sum===n;} const out=[]; for(let n=100;n<=999;n++){if(isA(n))out.push(n);} console.log(out);
                        

Output

JavaScript Program to Find the Sum of Natural Numbers

Sum 1..n.

                          function sumN(n){let s=0; for(let i=1;i<=n;i++){s+=i;} return s;} console.log(sumN(100));
                        

Output

JavaScript Program to Find HCF or GCD

Euclidean algorithm.

function gcd(a,b){while(b){[a,b]=[b,a%b];} return a;} console.log(gcd(48,18));

Output

JavaScript Program to Find LCM

LCM using GCD.

                          function gcd(a,b){while(b){[a,b]=[b,a%b];} return a;} function lcm(a,b){return Math.abs(a*b)/gcd(a,b);} console.log(lcm(12,18));
                        

Output

JavaScript Program to Find Sum of Natural Numbers Using Recursion

Recursive sum.

function sumN(n){return n<=1?n: n+sumN(n-1);} console.log(sumN(10));

Output

JavaScript Program to Find Factorial of Number Using Recursion

Recursive factorial.

function fact(n){return n<=1?1:n*fact(n-1);} console.log(fact(6));

Output

JavaScript Program to Find ASCII Value of Character

Use charCodeAt.

const ch="A"; console.log(ch.charCodeAt(0));

Output

Keep Practicing

Use the online compiler to run examples and test variations. Reinforce learning by building small scripts for each topic.

FAQ

Yes. You can copy the code into the JavaScript compiler page or your browser console to see the output. Some examples use console.log to print results.

Most examples use foundational syntax available in modern browsers. Where templates or arrow functions are used, they follow ES6 conventions widely supported today.

Absolutely. These examples are provided for learning. Copy, tweak values, and experiment to understand how the logic changes.

Start with Hello World, variables, and arithmetic. Then try control flow, functions, strings, and arrays to build confidence.

Learn JavaScript by Practicing Examples

Hands-on practice is the fastest way to understand JavaScript. Each example above focuses on a single concept—from strings, arrays, and objects to math utilities, dates, loops, and functions. Try editing variables, adding conditions, or refactoring logic, then observe the output changes instantly.

Use our tools to deepen your learning: JavaScript Compiler to run snippets, and the JavaScript Tutorial for guided theory and practice.

Beginner-Friendly

Start with variables, operators, and control flow. Build confidence with simple, readable programs.

Practical Patterns

Practice common tasks like formatting strings, manipulating arrays, and working with dates.

Grow Skills

Advance to objects, classes, and asynchronous patterns such as promises and async/await.

Math and Number Utilities

JavaScript Program to Display Fibonacci Sequence Using Recursion

Output

JavaScript Program to Find the Square Root

Output

JavaScript Program to Check Prime Number

Output

JavaScript Program to Print All Prime Numbers in an Interval

Output

JavaScript Program to Find the Factorial of a Number

Output

JavaScript Program to Display the Multiplication Table

Output

JavaScript Program to Print the Fibonacci Sequence

Output

JavaScript Program to Check Armstrong Number

Output

JavaScript Program to Find Armstrong Number in an Interval

Output

JavaScript Program to Find the Sum of Natural Numbers

Output

JavaScript Program to Find HCF or GCD

Output

JavaScript Program to Find LCM

Output

JavaScript Program to Find Sum of Natural Numbers Using Recursion

Output

JavaScript Program to Find Factorial of Number Using Recursion

Output

JavaScript Program to Find ASCII Value of Character

Output

Keep Practicing

FAQ

Can I run these examples in the browser?

Do I need ES6 features to follow these examples?

Can I copy and modify the examples?

Where should beginners start?

Learn JavaScript by Practicing Examples

Beginner-Friendly

Practical Patterns

Grow Skills