Js Events and selectors Flashcards
What is an event in JavaScript?
An event is an action or occurrence that happens in the browser, which can be detected and responded to by JavaScript.
True or False: Events in JavaScript can only be triggered by user interactions.
False
Fill in the blank: The method used to attach an event handler to an element is called ____.
addEventListener
What is the purpose of the ‘preventDefault()’ method?
The ‘preventDefault()’ method prevents the default action that belongs to the event from occurring.
Which of the following is NOT a type of event in JavaScript? (a) click (b) hover (c) submit (d) load
b) hover
What does the ‘this’ keyword refer to in an event handler?
In an event handler, ‘this’ refers to the element that triggered the event.
Short answer: What is event bubbling?
Event bubbling is the process where an event starts from the target element and bubbles up to the root of the DOM.
Short answer: What is event delegation?
Event delegation is a technique where a single event listener is added to a parent element to manage events for multiple child elements.
What is the function of ‘querySelector()’?
‘querySelector()’ returns the first element that matches a specified CSS selector.
True or False: ‘getElementById()’ can select multiple elements.
False
Fill in the blank: To select all elements with a specific class name, you use ____.
getElementsByClassName
Which method can be used to remove an event listener?
removeEventListener
Short answer: What is the purpose of ‘stopPropagation()’?
‘stopPropagation()’ prevents the event from bubbling up to parent elements.
What event is fired when a user clicks on an element?
The ‘click’ event.
True or False: You can use inline event handlers in HTML.
True
Fill in the blank: The event object is automatically passed to the event handler as a ____.
parameter
What does the ‘load’ event signify?
The ‘load’ event signifies that the entire page, including all dependent resources, has finished loading.
Which event occurs when a user presses a key?
The ‘keydown’ event.
Fill in the blank: You can select elements using CSS selectors with the method ____.
querySelectorAll
Short answer: What is the difference between ‘focus’ and ‘blur’ events?
‘focus’ occurs when an element gains focus, while ‘blur’ occurs when it loses focus.
What is the purpose of the ‘mouseenter’ event?
‘mouseenter’ is triggered when the mouse pointer enters the area of an element.
True or False: The ‘submit’ event is fired when a form is submitted.
True
Fill in the blank: To select an element by its tag name, you use ____.
getElementsByTagName
What does the ‘change’ event do?
The ‘change’ event is triggered when the value of an input element changes.
