JavaScript Constant (const) Tutorial

JavaScript Constant (const) Tutorial

Like other programming languages like C,PHP,Java … JavaScript also has Constant feature. As per “Constants are block-scoped, much like variables defined using the let statement. The value of a constant cannot change through re-assignment, and it can’t be redeclared “.

ES2015, the latest version of JavaScript, has a notion of const. So, most of the modern browser(latest version) like firefox, chrome, edge has const support.

JavaScript Constant Syntex :

const constantName = value1 , varname2 = value2,… varnameN = valueN;

JavaScript Constant Example

Create file called constant.html with code below

<!DOCTYPE html>
<html lang="en">
<meta charset="utf-8"/>
<title>JavaScript Constant example</title>
<h1>JavaScript Constant example</h1>
const height = 400;
const width = 400;
var newParagraph = document.createElement("p");
var newText = document.createTextNode("Height is : "+height+" Width  is : "+ width +". So, Area of the Rectangle is " + height*width +  " sq.ft.");

Now run web page constant.html in latest version of Chrome, Firefox, EDGE ,IE10.

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