13 Questions
What is the primary purpose of event delegation in event handling?
To reduce the number of event listeners
What happens when an event is triggered on a DOM element?
The event bubbles up the DOM tree and triggers the event handler
What is the benefit of updating DOM elements dynamically?
It improves the user experience by providing instant feedback
What is the relationship between event handling and application state?
Event handling updates the application state
What is the advantage of using event handling in a web application?
It provides a more interactive and engaging user experience
The document.querySelectorAll method returns a single element that matches the specified CSS selector.
False
The parentNode.appendChild method inserts a new node before the reference node.
False
The element.getAttribute method sets an attribute on an element.
False
The element.removeEventListener method adds an event listener to an element.
False
The document.createElement method creates a new element with the specified ID.
False
The element.getElementsByTagName method selects all elements with the specified class name.
False
The element.addEventListener method only works for mouse events.
False
The parentNode.removeChild method appends a child node to the parent node.
False
Study Notes
Element Selection
-
document.getElementById(id)is used to select an element with a specified ID -
document.querySelector(selector)selects the first element that matches a specified CSS selector -
document.querySelectorAll(selector)selects all elements that match a specified CSS selector -
element.getElementsByClassName(className)selects all elements with a specified class name -
element.getElementsByTagName(tagName)selects all elements with a specified tag name
DOM Manipulation
Creating Elements
-
document.createElement(tagName)creates a new element with a specified tag name
Appending and Inserting Elements
-
parentNode.appendChild(childNode)appends a child node to a parent node -
parentNode.insertBefore(newNode, referenceNode)inserts a new node before a reference node
Removing Elements
-
parentNode.removeChild(childNode)removes a child node from a parent node
Modifying Element Attributes and Properties
-
element.setAttribute(attributeName, attributeValue)sets an attribute on an element -
element.getAttribute(attributeName)gets the value of an attribute on an element -
element.property = valuesets a property on an element (e.g.element.src = 'image.jpg')
Event Listeners
Types of Events
- Mouse events (e.g.
click,mouseover,mouseout) - Keyboard events (e.g.
keydown,keyup) - Form events (e.g.
submit,change) - Window events (e.g.
load,resize)
Adding Event Listeners
-
element.addEventListener(eventType, listener)adds an event listener to an element -
element.removeEventListener(eventType, listener)removes an event listener from an element
Event Listener Functions
-
function(event) {...}is a function that is called when an event occurs -
event.targetis the element that triggered the event -
event.preventDefault()prevents the default action of the event from occurring
This quiz covers event handling and event delegation in JavaScript, including responding to user interactions and dynamically updating DOM elements.
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