JavaScript Functions and Events Mocktest

The oninput event in HTML is used to track changes made to form inputs. It triggers whenever the value of an input field changes, such as when a user types or deletes text in a text input or selects an option in a dropdown, allowing developers to handle input changes dynamically.

The correct way to add a click event listener to the button with the ID myButton is by using the addEventListener() method as shown in Option B. This method ensures proper event handling and allows for attaching multiple event listeners to the same element without overwriting existing ones.

The removeEventListener() method is used to remove an event listener from an HTML element in JavaScript. It requires specifying the event type and the function (or reference) used as the event listener, allowing developers to detach event handlers when they are no longer needed.

The onmouseover event in HTML is used to detect when an element is hovered over by the mouse pointer. It triggers when the mouse cursor moves over the specified element, allowing developers to create hover effects or perform actions when the user hovers over a particular area.

The onload event is triggered when a web page finishes loading. It indicates that all resources (like images, scripts, and stylesheets) on the page have been loaded, allowing developers to execute JavaScript code or perform actions after the entire page and its contents are ready.

The addEventListener() method in JavaScript is used to attach event listeners to HTML elements. It allows developers to define functions (event handlers) that execute in response to specific events on the specified elements, enhancing interactivity and enabling dynamic behavior in web pages.

The given JavaScript code adds a keypress event listener to the entire document. When a key is pressed while the document has focus, the specified function logs the pressed key's value to the console, allowing developers to handle keyboard input and perform actions based on the keys pressed.

The onsubmit event occurs when a user submits an HTML form. It is commonly used to handle form submissions and allows developers to execute functions or perform validation checks before submitting form data to a server or processing it further on the client side.

The preventDefault() method in JavaScript event handling prevents the default behavior associated with an event, such as submitting a form, following a link, or executing a browser's default action. It allows developers to control how events are handled and customize the behavior based on specific requirements.

JavaScript event bubbling refers to the upward propagation of events from child elements to parent elements in the document tree. When an event occurs on a nested (child) element, it also triggers the same event on its parent elements, propagating upwards until reaching the root (document).