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 event is triggered when a web page finishes loading?
A). A. onload
B). B. onsubmit
C). C. onmouseover
D). D. onclick
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'); });
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
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
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 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; }
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
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
What is the purpose of the oninput event in HTML?
A). A. To track changes in form inputs
B). B. To detect mouse movements
C). C. To determine when an element is loaded
D). D. To handle form submissions