What does the preventDefault() method do in JavaScript event handling?
A). A. Stops event propagation to parent elements
B). B. Prevents the default behavior associated with an event
C). C. Detaches event listeners from elements
D). D. Clears the event queue
Which method is used to attach an event listener to an HTML element in JavaScript?
A). A. appendEvent()
B). B. addEventListener()
C). C. attachEvent()
D). D. bindEvent()
Which statement accurately describes JavaScript event bubbling?
A). A. It refers to the downward propagation of events from parent elements to child elements.
B). B. It refers to the upward propagation of events from child elements to parent elements.
C). C. It refers to the simultaneous firing of multiple events on the same element.
D). D. It refers to the automatic removal of event listeners after an event is triggered.
Consider the following JavaScript code: document.addEventListener('keypress', function(event) { console.log('Key pressed:', event.key); }); What does this code do?
A). A. Adds a click event listener to the document
B). B. Adds a keypress event listener to the document
C). C. Removes a keypress event listener from the document
D). D. Checks if a key is pressed while hovering over an element
Consider the following JavaScript code: let greet = function(name) { return 'Hello, ' + name + '!'; }; What type of function is greet in this code?
A). A. Named function
B). B. Anonymous function
C). C. Arrow function
D). D. Generator function
What is the purpose of the onclick attribute in HTML elements?
A). A. To define styles for HTML elements
B). B. To attach event listeners for mouse clicks
C). C. To insert JavaScript code directly into HTML
D). D. To create animations for HTML elements
What is the purpose of the onmouseover event in HTML?
A). A. To detect when an element is hovered over
B). B. To track changes in form inputs
C). C. To determine when an element is loaded
D). D. To handle form submissions
What is the purpose of parameters in a JavaScript function?
A). A. To return a value from the function
B). B. To define the function's name
C). C. To store variables within the function
D). D. To accept inputs into the function
How can you attach multiple event listeners to the same HTML element in JavaScript without overwriting existing ones?
A). A. By using the attachEvent() method
B). B. By using the addEventListener() method with the replace parameter
C). C. By assigning multiple functions directly to the element's event attributes (e.g., onclick, onmouseover)
D). D. By using the addEventListener() method multiple times for the same event
Which type of JavaScript function is defined without a name?
A). A. Named function
B). B. Anonymous function
C). C. Arrow function
D). D. Generator function