Change Class of HTML Tag Using JavaScript

In this tutorial we will see how to Change Class of HTML Tag Using JavaScript. The getElementById() Method and HTML DOM className Property is used for this purpose.


HTML Code is given below, This code contains a paragraph element and a button element.

<!DOCTYPE html>
<html lang="en">
<meta charset="utf-8">
<title>Change Class of HTML Tag Using JavaScript</title>  
<p id='main' class='one'>Change my Class using JavaScript</p>
<button onclick="changeClass()">Change Class</button>  

getElementById() Method

The getElementById() Method is used to get or select or target the HTML element with a specified value of Id attribute.

In this example the id of paragraph element is 'main'. This id is used to target or select the paragraph element.

getElementById() Method is supported by all major browsers.

className Property

The JavaScript className Property sets or returns the class name of an element.

The JavaScript className Property is supported by all major browsers.

JavaScript Code

In this example getElementById method is used to select the paragraph tag. Then className property is used to change the class of the paragraph tag.

onclick event is used to trigger the main function (changeClass()) which performs this task.

Take a look at the code given below.

function changeClass()
document.getElementById("main").className = "two";

Video Tutorial

Watch video tutorial and demo on how to Change Class of HTML Tag Using JavaScript.

Count Number of Rows in Table using JavaScript Move Background Image with Mouse Using JavaScript Disable Text Selection Using JavaScript Get Selected Radio Button Value On Click using JavaScript Get input Element Value On Click Using JavaScript Get All Options In Select Tag using JavaScript Enable and Disable Button using JavaScript Get Class of Clicked Element Using JavaScript Toggle Text of HTML Element with JavaScript onclick Call Multiple Functions on one click using JavaScript onclick Check UnCheck all Checkboxes with JavaScript Open Select File Dialog Box Using JavaScript Display Message When File Is Selected Using JavaScript Get Current Page URL using JavaScript Get ID of Clicked Element using JavaScript How To Delay JavaScript Function Call Change Background Color onclick using JavaScript Change Class of HTML Tag Using JavaScript Get Clicked HTML Element Name Using JavaScript Execute a Function on Hover Using JavaScript Delete HTML Element using JavaScript Change HTML Attribute Value using JavaScript Replace a Word from everywhere in a String using JavaScript Show and Hide Element On Click Using JavaScript Passing JavaScript Value from one Page to another T-Rex Run Game Hacked - Hack T Rex Run Game How To Use JavaScript Function as Variable Display Current Date and Time Using HTML and JAVASCRIPT Get Unicode Value of Pressed Keyboard Key using JavaScript Detect Enter Key Press Using JavaScript Hide and Show Element on Enter Key Press Get Mouse Cursor Position in Pixels using JavaScript Open Link in New Window using JavaScript Open Link in New Tab using JavaScript Get Image Width and Height using JavaScript Remove Last Digit of Number using JavaScript Bitwise OR Simple JavaScript Calculator Using Vanilla JavaScript Disable Right Click on Website Using JavaScript How To Add Line Breaks in JavaScript Alert Box Add Class to HTML Tag On Click using JavaScript