Lecture 159:- Event Handling

Event handling refers to the process of capturing, processing, and responding to events that occur in a web page. Events are user actions or occurrences that happen in the browser such as clicking a button, typing in an input field, or scrolling the page.

In JavaScript, event handling is typically done using event listeners. An event listener is a function that waits for an event to occur and then executes a set of instructions when the event is detected. Event listeners are added to DOM elements using the addEventListener() method.

The syntax for adding an event listener to an element is as follows:

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element.addEventListener(event, function, useCapture);

Here, element is the DOM element that the event listener is attached to, event is the event to listen for (e.g. "click", "keydown"), function is the function that is executed when the event occurs, and useCapture is an optional boolean value that determines whether the event should be handled in the capturing or bubbling phase.

For example, the following code adds an event listener to a button element that logs a message to the console when the button is clicked:

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const button = document.querySelector('#myButton'); button.addEventListener('click', function() {  console.log('Button clicked!'); });