Declaration

function greet() {

    console.log("Hello");

}

Expression

const greet = function() {

    console.log("Hello");

}

const add = (a, b) => a + b;

console.log(add(2,3));

Output

5

A function passed as an argument to another function.

function greet(name, callback) {

    console.log("Hi " + name);

    callback();

}

greet("Siva", function() {

    console.log("Welcome");

});

let arr = [10,20,30];

for(let i=0;i<arr.length;i++){}

for(let value of arr){}

let obj = {name:"Siva"};

for(let key in obj){}

DOM (Document Object Model) represents the HTML document as objects.

Example

document.getElementById("title");

document.getElementById("id");

document.querySelector(".box");

document.querySelectorAll("p");

element.innerHTML = "<b>Hello</b>";

Displays bold text.

element.textContent = "<b>Hello</b>";

Displays the actual tags as text.