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 are used for this purpose.

HTML Code

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

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

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.

<script>
function changeClass()
{
document.getElementById("main").className = "two";
}
</script>

Demo

Video Tutorial

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

How To Scroll Page to Bottom using JavaScript How To Detect Shift Key Press with JavaScript Change Text Color On Hover with JavaScript Hide and Show div using JavaScript Get Button text with JavaScript Get textarea value with JavaScript Get table row Height with JavaScript Auto Increase width of input field with JavaScript Set Textarea maxLength with JavaScript Set Textarea Value with JavaScript JavaScript Count list items JavaScript set input field value Count Button Clicks with JavaScript Scroll Page to the Top on Click with JavaScript Change id of Element with JavaScript JavaScript Change li Text Color JavaScript Change li Text JavaScript Remove id from Element Check If id Exists in JavaScript How To Delete Table Row by id in JavaScript Update Textarea value in JavaScript Change Variable Value in JavaScript Uncheck Radio Button Dynamically JavaScript Check Radio Button Dynamically JavaScript JavaScript Check if Radio Button is Checked or Not