Here are Top 50 multiple-choice questions (MCQs) focused on the HTML5 features and elements in JavaScript MCQs, along with their answers and explanations.
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1. What is event handling in JavaScript?
- Controlling the flow of execution
- Managing data storage
- Responding to user interactions or browser events
- Creating HTML elements
Event handling in JavaScript involves responding to user interactions or browser events.
2. Which HTML attribute is used to specify the JavaScript code that should be executed when an event occurs?
- `script`
- `code`
- `onEvent`
- `onclick`
The `onEvent` attribute (e.g., `onclick`, `onmouseover`) is used to specify JavaScript code for event handling.
3. What is an event listener in JavaScript?
- A built-in JavaScript function
- A type of HTML element
- A piece of code that "listens" for and responds to events
- An HTML tag
An event listener is a piece of code that "listens" for and responds to events.
4. Which function is used to add an event listener to an HTML element in JavaScript?
- `addEventListener()`
- `attachEvent()`
- `listenForEvent()`
- `addEvent()`
The `addEventListener()` function is used to add an event listener to an HTML element in JavaScript.
5. What is the purpose of the `event` object in JavaScript event handling?
- To create new events
- To represent the element that triggered the event
- To store data for the event
- To provide information about the event
The `event` object in JavaScript provides information about the event, such as the type, target element, and event details.
6. Which event type occurs when an HTML element loses focus?
- `click`
- `mouseover`
- `focus`
- `blur`
The `blur` event occurs when an HTML element loses focus.
7. What is event propagation in JavaScript event handling?
- The process of generating events
- The order in which events occur
- The flow of events from the target element to the root of the DOM tree
- The timing of events
Event propagation in JavaScript refers to the flow of events from the target element to the root of the DOM tree.
8. Which method is used to prevent the default behavior of an event in JavaScript?
- `stopEvent()`
- `preventDefault()`
- `disableEvent()`
- `defaultPrevent()`
The `preventDefault()` method is used to prevent the default behavior of an event in JavaScript.
9. What is event delegation in JavaScript event handling?
- The process of generating events
- The propagation of events to multiple elements
- The use of a single event listener on a parent element to handle events for its children
- The combination of multiple events into one
Event delegation in JavaScript involves using a single event listener on a parent element to handle events for its children.
10. Which method is used to stop the propagation of an event in JavaScript?
- `stopPropagation()`
- `preventPropagation()`
- `cancelPropagation()`
- `event.stopPropagation()`
The `stopPropagation()` method is used to stop the propagation of an event in JavaScript.
11. Which event type occurs when a user clicks on an HTML element with the left mouse button?
- `mousedown`
- `mouseup`
- `click`
- `mouseover`
The `click` event occurs when a user clicks on an HTML element with the left mouse button.
12. What is event bubbling in JavaScript event handling?
- The process of generating events
- The order in which events occur
- The flow of events from the root of the DOM tree to the target element
- The timing of events
Event bubbling in JavaScript is the flow of events from the root of the DOM tree to the target element.
13. Which event type occurs when a user hovers the mouse pointer over an HTML element?
- `mouseover`
- `mouseenter`
- `mouseout`
- `mousemove`
The `mouseover` event occurs when a user hovers the mouse pointer over an HTML element.
14. What is the purpose of the `stopImmediatePropagation()` method in JavaScript event handling?
- To stop event propagation
- To prevent the default behavior of an event
- To prevent other listeners on the same element from being called
- To start event propagation
The `stopImmediatePropagation()` method in JavaScript is used to prevent other listeners on the same element from being called.
15. Which event type occurs when a user presses a key on the keyboard?
- `keydown`
- `keypress`
- `keyup`
- `keypressdown`
The `keydown` event occurs when a user presses a key on the keyboard.
16. What is the purpose of the `event.currentTarget` property in JavaScript event handling?
- To get the event target element
- To get the event type
- To get the currently focused element
- To get the element to which the event listener is attached
The `event.currentTarget` property in JavaScript is used to get the element to which the event listener is attached.
17. Which event type occurs when an HTML element is being dragged?
- `dragstart`
- `dragmove`
- `dragging`
- `dragged`
The `dragstart` event occurs when an HTML element is being dragged.
18. What is the purpose of the `event.target` property in JavaScript event handling?
- To get the event type
- To get the currently focused element
- To get the element to which the event listener is attached
- To get the event target element
The `event.target` property in JavaScript is used to get the event target element.
19. Which method is used to remove an event listener in JavaScript?
- `removeEventListener()`
- `detachEventListener()`
- `removeEvent()`
- `offEvent()`
The `removeEventListener()` method is used to remove an event listener in JavaScript.
20. What is the purpose of the `mouseenter` event in JavaScript event handling?
- To detect when the mouse pointer enters an element
- To detect mouse movement
- To detect when the mouse pointer leaves an element
- To detect keyboard input
The `mouseenter` event is used to detect when the mouse pointer enters an element.
21. Which event type occurs when a user releases the mouse button after clicking on an HTML element?
- `mousedown`
- `mouseup`
- `click`
- `dblclick`
The `mouseup` event occurs when a user releases the mouse button after clicking on an HTML element.
22. What is the purpose of the `event.preventDefault()` method in JavaScript event handling?
- To stop event propagation
- To prevent other listeners on the same element from being called
- To prevent the default behavior of an event
- To start event propagation
The `event.preventDefault()` method is used to prevent the default behavior of an event in JavaScript.
23. Which event type occurs when a user double-clicks on an HTML element?
- `click`
- `dblclick`
- `doubleclick`
- `doubleclicking`
The `dblclick` event occurs when a user double-clicks on an HTML element.
24. What is the purpose of the `focus` event in JavaScript event handling?
- To detect when an element gains focus
- To detect mouse movement
- To detect when an element loses focus
- To detect keyboard input
The `focus` event is used to detect when an element gains focus.
25. Which event type occurs when a user moves the mouse pointer over an HTML element?
- `click`
- `mouseover`
- `mouseenter`
- `mousemove`
The `mousemove` event occurs when a user moves the mouse pointer over an HTML element.
26. What is event propagation in JavaScript event handling?
- The process of generating events
- The order in which events occur
- The flow of events from the target element to the root of the DOM tree
- The timing of events
Event propagation in JavaScript refers to the flow of events from the target element to the root of the DOM tree.
27. Which event type occurs when a user hovers the mouse pointer over an HTML element?
- `mouseover`
- `mouseenter`
- `mouseout`
- `mousemove`
The `mouseover` event occurs when a user hovers the mouse pointer over an HTML element.
28. What is the purpose of the `stopImmediatePropagation()` method in JavaScript event handling?
- To stop event propagation
- To prevent the default behavior of an event
- To prevent other listeners on the same element from being called
- To start event propagation
The `stopImmediatePropagation()` method in JavaScript is used to prevent other listeners on the same element from being called.
29. Which event type occurs when a user presses a key on the keyboard?
- `keydown`
- `keypress`
- `keyup`
- `keypressdown`
The `keydown` event occurs when a user presses a key on the keyboard.
30. What is the purpose of the `event.currentTarget` property in JavaScript event handling?
- To get the event target element
- To get the event type
- To get the currently focused element
- To get the element to which the event listener is attached
The `event.currentTarget` property in JavaScript is used to get the element to which the event listener is attached.
31. Which event type occurs when an HTML element is being dragged?
- `dragstart`
- `dragmove`
- `dragging`
- `dragged`
The `dragstart` event occurs when an HTML element is being dragged.
32. What is the purpose of the `event.target` property in JavaScript event handling?
- To get the event type
- To get the currently focused element
- To get the element to which the event listener is attached
- To get the event target element
The `event.target` property in JavaScript is used to get the event target element.
33. Which method is used to remove an event listener in JavaScript?
- `removeEventListener()`
- `detachEventListener()`
- `removeEvent()`
- `offEvent()`
The `removeEventListener()` method is used to remove an event listener in JavaScript.
34. What is the purpose of the `mouseenter` event in JavaScript event handling?
- To detect when the mouse pointer enters an element
- To detect mouse movement
- To detect when the mouse pointer leaves an element
- To detect keyboard input
The `mouseenter` event is used to detect when the mouse pointer enters an element.
35. Which event type occurs when a user releases the mouse button after clicking on an HTML element?
- `mousedown`
- `mouseup`
- `click`
- `dblclick`
The `mouseup` event occurs when a user releases the mouse button after clicking on an HTML element.
36. What is the purpose of the `event.preventDefault()` method in JavaScript event handling?
- To stop event propagation
- To prevent other listeners on the same element from being called
- To prevent the default behavior of an event
- To start event propagation
The `event.preventDefault()` method is used to prevent the default behavior of an event in JavaScript.
37. Which event type occurs when a user double-clicks on an HTML element?
- `click`
- `dblclick`
- `doubleclick`
- `doubleclicking`
The `dblclick` event occurs when a user double-clicks on an HTML element.
38. What is the purpose of the `focus` event in JavaScript event handling?
- To detect when an element gains focus
- To detect mouse movement
- To detect when an element loses focus
- To detect keyboard input
The `focus` event is used to detect when an element gains focus.
39. Which event type occurs when a user moves the mouse pointer over an HTML element?
- `click`
- `mouseover`
- `mouseenter`
- `mousemove`
The `mousemove` event occurs when a user moves the mouse pointer over an HTML element.
40. What is the purpose of the `event.stopPropagation()` method in JavaScript event handling?
- To start event propagation
- To stop the propagation of an event
- To prevent other listeners on the same element from being called
- To prevent the default behavior of an event
The `event.stopPropagation()` method is used to stop the propagation of an event in JavaScript.
41. Which event type occurs when an HTML element gains focus?
- `click`
- `mouseover`
- `mouseenter`
- `focus`
The `focus` event occurs when an HTML element gains focus.
42. What is event delegation in JavaScript event handling?
- The process of generating events
- The propagation of events to multiple elements
- The use of a single event listener on a parent element to handle events for its children
- The combination of multiple events into one
Event delegation in JavaScript involves using a single event listener on a parent element to handle events for its children.
43. Which method is used to trigger an event in JavaScript?
- `fireEvent()`
- `triggerEvent()`
- `dispatchEvent()`
- `simulateEvent()`
The `dispatchEvent()` method is used to trigger or dispatch an event in JavaScript.
44. What is the purpose of the `mouseleave` event in JavaScript event handling?
- To detect when the mouse pointer enters an element
- To detect when the mouse pointer leaves an element
- To detect mouse movement
- To detect when an element gains focus
The `mouseleave` event is used to detect when the mouse pointer leaves an element.
45. Which event type occurs when a user clicks the right mouse button on an HTML element?
- `click`
- `contextmenu`
- `mousedown`
- `mouseup`
The `contextmenu` event occurs when a user clicks the right mouse button on an HTML element.
46. What is the purpose of the `event.type` property in JavaScript event handling?
- To get the target element
- To get the event type
- To get the currently focused element
- To get the element to which the event listener is attached
The `event.type` property in JavaScript is used to get the event type.
47. Which event type occurs when a user scrolls an HTML element?
- `scroll`
- `scrolling`
- `scrolled`
- `scrollstart`
The `scroll` event occurs when a user scrolls an HTML element.
48. What is the purpose of the `mouseleave` event in JavaScript event handling?
- To detect when the mouse pointer enters an element
- To detect when the mouse pointer leaves an element
- To detect mouse movement
- To detect when an element gains focus
The `mouseleave` event is used to detect when the mouse pointer leaves an element.
49. Which event type occurs when a user right-clicks on an HTML element?
- `click`
- `contextmenu`
- `mousedown`
- `mouseup`
The `contextmenu` event occurs when a user right-clicks on an HTML element.
50. What is the purpose of the `event.stopPropagation()` method in JavaScript event handling?
- To start event propagation
- To stop the propagation of an event
- To prevent other listeners on the same element from being called
- To prevent the default behavior of an event
The `event.stopPropagation()` method is used to stop the propagation of an event in JavaScript.
