Consider the following HTML code: Which JavaScript code adds a click event listener to the button?
A). A. document.getElementById('myButton').onclick = function() { alert('Button clicked'); };
B). B. document.getElementById('myButton').addEventListener('click', function() { alert('Button clicked'); });
C). C. document.getElementById('myButton').click(function() { alert('Button clicked'); });
D). D. document.getElementById('myButton').on('click', function() { alert('Button clicked'); });
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()
What is the primary purpose of JavaScript functions?
A). A. To style web pages
B). B. To provide structure to HTML elements
C). C. To create reusable code blocks
D). D. To define CSS styles for HTML
What is the purpose of the removeEventListener() method in JavaScript?
A). A. To add event listeners to HTML elements
B). B. To detach event listeners from HTML elements
C). C. To prevent event propagation in event handling
D). D. To modify HTML content dynamically
Which of the following correctly defines a JavaScript function?
A). A. function addNumbers(num1, num2) { return num1 + num2; }
B). B. function = addNumbers(num1, num2) { return num1 + num2; }
C). C. function addNumbers(num1 + num2) { return num1 + num2; }
D). D. function addNumbers(num1, num2) => { return num1 + num2; }
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
Which event occurs when a user submits an HTML form?
A). A. onsubmit
B). B. onmouseover
C). C. onkeydown
D). D. onclick
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 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
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