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DOM Events and Event Handling in JavaScript (Live Playground)

In this tutorial, we'll learn about DOM events and event handling in JavaScript, which are essential for creating interactive web applications. By understanding DOM events, you'll be able to add functionality to your web pages, such as responding to user interactions like clicks, keyboard input, and more.

What are DOM events?​

DOM events are actions or occurrences that happen in the browser, usually triggered by user interactions. Examples of DOM events include:

  • Clicking on a button or link
  • Pressing a key on the keyboard
  • Moving the mouse over an element
  • Submitting a form
  • Loading a web page

JavaScript allows you to listen for these events and perform actions when they occur, making your web pages more interactive and engaging.

Listening for DOM events​

To listen for a DOM event, you can use the addEventListener method on an HTML element. The addEventListener method takes two arguments:

  1. The event type (e.g., click, mouseover, keydown, etc.)
  2. A callback function that will be executed when the event occurs

Here's an example of how to use the addEventListener method to listen for a click event on a button:

<!DOCTYPE html>
<html>
  <head>
    <title>DOM Event Example</title>
  </head>
  <body>
    <button id="myButton">Click me!</button>

    <script>
      // Get a reference to the button element
      var button = document.getElementById('myButton');

      // Add a click event listener to the button
      button.addEventListener('click', function () {
        alert('Button clicked!');
      });
    </script>
  </body>
</html>

In this example, when the button is clicked, an alert will be displayed with the message "Button clicked!"

Event object​

When an event is triggered, the browser creates an event object with details about the event, such as the type of event, the target element, the timestamp, and more. This event object is automatically passed as the first argument to your callback function.

Here's an example of how to access the event object:

button.addEventListener('click', function (event) {
  console.log('Event type:', event.type); // Outputs "Event type: click"
  console.log('Target element:', event.target);
});

In this example, the event object is used to access the event type and target element.

Live Playground, Try it Yourself

Conclusion​

DOM events are an essential part of creating interactive web applications, allowing you to respond to user interactions and perform actions when events occur. By understanding what DOM events are and how to work with them using JavaScript, you'll be well-equipped to create dynamic, engaging web experiences.