DOM Animations u0026 User Input: Sequencing, Debouncing, and Throttling Quiz

Test your knowledge of sequencing animations in the DOM using scroll and user input events, with a special focus on debouncing and throttling techniques to optimize performance and user experience.

1. Debouncing Basics

   What is the main purpose of using debouncing when handling frequent scroll or input events in web animations?

   1. To increase the animation speed
   2. To reduce the rate at which the event handler is executed
   3. To slow down the user's device
   4. To prevent the scroll event from being captured

2. Throttling vs Debouncing

   Which statement best describes throttling in the context of event handling for DOM animations?

   1. It delays the event handler until the event stops happening
   2. It stops animations from starting
   3. It ignores all user inputs
   4. It ensures the event handler executes once per a specified time interval regardless of how many times the event fires

3. Animation Sequence Example

   When triggering a sequence of animations with a button click, what should you use to avoid overlapping animations due to rapid clicking?

   1. Increase the animation frame rate
   2. Use an infinite timeout
   3. Debounce the click event handler
   4. Disable JavaScript

4. Scroll Event Impact

   Why can handling every scroll event directly cause performance issues in DOM-based animations?

   1. Scroll events can fire very frequently, overwhelming the browser’s rendering process
   2. Scroll events only trigger on page load
   3. Scroll events are rare and not optimized
   4. Scroll events always require server requests

5. Debounce Delay Example

   If you debounce an input event with a 300ms delay, when does the event handler execute as a user types quickly?

   1. 300ms after the last keystroke
   2. Once every 10 seconds
   3. Never
   4. Immediately after every keypress

6. Sequencing Animations

   Which technique can ensure two related animations run one after the other in response to a user action?

   1. Run both animations simultaneously on the same element
   2. Start the second animation after the first animation's end event
   3. Use animation throttling exclusively
   4. Trigger both animations in separate threads

7. Throttle Timing

   When throttling a scroll-based animation to 100ms, what happens if the user scrolls continuously?

   1. The animation handler runs after each pixel moved
   2. The animation handler runs at most once every 100 milliseconds
   3. The animation never executes
   4. The handler waits for scrolling to stop before running

8. Debounce Implementation

   Which built-in timer function is commonly used to implement debouncing in JavaScript?

   1. eventListener
   2. setImmediate
   3. getInterval
   4. setTimeout

9. Performance Gains

   How does debouncing or throttling improve user experience during DOM-related animations on scroll or input?

   1. By removing the event entirely
   2. By lowering the browser resolution
   3. By preventing excessive computations and reducing lag
   4. By skipping all animations

10. Incorrect Debouncing

    What could be a consequence of using too long a debounce delay for a scroll-triggered animation?

    1. The animation automatically restarts
    2. The scroll event stops firing altogether
    3. The animation feels slow or unresponsive to the user's scroll
    4. The animation plays smoothly every time