How to Use JavaScript to Modify the Class of an HTML Element

Mia Chevalier
Thursday, June 27, 2024 at 1:34:44 PM
JavaScript

Updating Classes with JavaScript

JavaScript offers extensive tools for dynamically interacting with and manipulating HTML components. One common duty is to modify the class of an HTML element in response to events such as onclick.

This post will show you how to utilize JavaScript to update an element's class, allowing for dynamic styling and behavior changes on your web pages. These strategies, whether used in response to a button click or another event, will improve your web development skills.

Command Description
className Sets or returns an element's class attribute. Used to modify the element's class.
getElementById Returns the element with the ID attribute set to the provided value. Used to choose the button element.
onclick Sets the function that will be run when the element is clicked.
removeClass JQuery removes one or more class names from the specified components.
addClass JQuery adds one or more class names to the selected components.
$ Alias for jQuery, which is used to select and manipulate items.

Understanding JavaScript Class Manipulation

The included scripts show how to change the class of an HTML element using JavaScript and jQuery in response to a click event. The first script achieves this capability through the use of ordinary JavaScript. The technique is used to pick the button element with ID'myButton'. The event is then assigned to this element, defining the function that will be executed when the button is clicked. Within this method, the button's attribute is set to 'changed', updating its class and then its style as described in CSS. This script demonstrates the simplicity and directness of utilizing plain JavaScript for DOM manipulation.

The second script demonstrates the same capability with jQuery, a popular JavaScript tool that simplifies HTML page navigation and manipulation. Here, the jQuery alias is used to pick the button element. The method is then used to add an event handler for the click event. This handler modifies the button's class using jQuery's and addClass methods. These methods make it easier to manage the element's classes while remaining more readable and concise than simple JavaScript. Both scripts aim to show how different techniques can achieve the same goal: dynamically modifying an element's class based on user interaction.

Changing an Element's Class on Click with JavaScript

JavaScript and HTML

// HTML
<!DOCTYPE html>
<html>
<head>
<title>Change Class Example</title>
<style>
  .original { color: blue; }
  .changed { color: red; }
</style>
</head>
<body>
<button id="myButton" class="original">Click me</button>
<script>
  document.getElementById('myButton').onclick = function() {
    this.className = 'changed';
  };
</script>
</body>
</html>

Updating an HTML Element's Class with jQuery

JavaScript with jQuery

// HTML
<!DOCTYPE html>
<html>
<head>
<title>Change Class with jQuery</title>
<style>
  .original { color: blue; }
  .changed { color: red; }
</style>
</head>
<body>
<button id="myButton" class="original">Click me</button>
<script src="https://code.jquery.com/jquery-3.6.0.min.js"></script>
<script>
  $('#myButton').click(function() {
    $(this).removeClass('original').addClass('changed');
  });
</script>
</body>
</html>

Advanced Methods for Class Manipulation in JavaScript

Beyond simple class modifications in response to events, JavaScript provides more complicated methods for modifying an element's class list. The property, for example, offers a more adaptable and powerful approach to dealing with classes. The property provides a live DOMTokenList collection of the element's class properties. Using , you can add, remove, toggle, and check for classes without affecting other classes that may be used on the element.

The method adds classes to an element, while the method removes them. The function is very handy because it creates the class if it does not exist and removes it if it does, making it suitable for jobs like providing dark mode toggles. Furthermore, the contains method checks if the element contains a certain class. This can be handy for conditionally applying styles or actions based on the current state of an element.

  1. How can I assign several classes to an element?
  2. Apply the method with additional arguments: .
  3. Can I remove every class from an element?
  4. Yes, you may use the attribute to set an empty string: .
  5. What is the distinction between and ?
  6. sets or obtains the full class property, while enables more granular class manipulation.
  7. How can I determine whether an element has a specific class?
  8. Follow the method: .
  9. How can I change a class on an element?
  10. Apply the method: .
  11. Can I use jQuery to alter classes?
  12. Yes, jQuery has methods such as , , and .
  13. What is the definition of a live DOMTokenList?
  14. A is a live collection that automatically updates as the element's class attribute changes.
  15. Is supported in every browser?
  16. All modern browsers support . However, earlier versions of Internet Explorer may not completely support it.
  17. How can I dynamically add classes depending on conditions?
  18. To conditionally apply classes, combine statements with or .

Key Techniques For Dynamic Class Changes

The included scripts show how to change the class of an HTML element using JavaScript and jQuery in response to a click event. The first script achieves this capability through the use of ordinary JavaScript. The technique is used to pick the button element with ID'myButton'. The event is then assigned to this element, defining the function that will be executed when the button is clicked. Within this method, the button's attribute is set to 'changed', updating its class and then its style as described in CSS. This script demonstrates the simplicity and directness of utilizing plain JavaScript for DOM manipulation.

The second script demonstrates the same capability with jQuery, a popular JavaScript tool that simplifies HTML page navigation and manipulation. Here, the jQuery alias is used to pick the button element. The method is then used to add an event handler for the click event. This handler modifies the button's class using jQuery's and addClass methods. These methods make it easier to manage the element's classes while remaining more readable and concise than simple JavaScript. Both scripts aim to show how different techniques can achieve the same goal: dynamically modifying an element's class based on user interaction.

Manipulating an HTML element's class with JavaScript or jQuery is a simple approach to dynamically adjust its styling and behavior. Using methods such as , , and jQuery's class manipulation methods, developers may improve the interactivity and responsiveness of their web pages, making them more engaging for users.