What is a function in JavaScript?

A function is a reusable block of code designed to perform a specific task.

How do you call a function?

You call a function by writing its name followed by parentheses, like myFunction().

Functions help avoid repetition, improve organization, and make code reusable.

A function in JavaScript is a block of code designed to perform a specific task.

Instead of writing the same code again and again, you can write it once inside a function and reuse it whenever needed.

💡 Simple idea

A function is like a machine: you give input, it does something, and gives output.

// function declaration
function greet() {
  console.log("Hello!");
}

A function only runs when you call it:

greet(); // Hello!

Functions can take inputs called parameters.

function greet(name) {
  console.log("Hello " + name);
}

greet("Rahul");
greet("Aisha");

Functions can also return results.

function add(a, b) {
  return a + b;
}

let result = add(5, 3);
console.log(result);

// arrow function
const multiply = (a, b) => a * b;

Functions are reusable blocks of code that perform tasks. They are one of the most important building blocks in JavaScript programming.

Once you understand functions, you can build much more powerful programs.