Optimizing Performance: Transforms, Opacity, and Rendering Techniques Quiz

Test your understanding of performance and rendering optimizations in web development, including the use of transforms and opacity, requestAnimationFrame, and strategies to minimize reflow and repaint. This quiz helps you identify best practices for smooth and efficient UI updates.

1. Efficient Animations

   Which CSS property is commonly recommended for smooth animations because it does not trigger layout recalculations or cause reflow?

   1. transform
   2. margin
   3. width
   4. font-size

2. Reflow Minimization

   When you animate an element by changing only its opacity, how does this typically affect reflow and repaint in the browser?

   1. Only reflow is triggered
   2. Both reflow and repaint are triggered
   3. Neither reflow nor repaint is triggered
   4. Only repaint is triggered, not reflow

3. Choosing the Best Property

   If you need to move an element smoothly across the screen, which property should you animate to ensure better performance?

   1. border
   2. transform
   3. left
   4. height

4. Understanding requestAnimationFrame

   Which JavaScript method should be used to schedule smooth visual updates in sync with the browser’s refresh rate?

   1. requestAnimationFrame
   2. clearInterval
   3. setTimeot
   4. setInterval

5. Avoiding Layout Thrashing

   Reading layout properties like offsetWidth immediately after changing element style can cause multiple reflows, a problem commonly known as what?

   1. Repainting
   2. Opacity flickering
   3. Layout thrashing
   4. Render jank

6. Repaint Causes

   Which CSS change is most likely to cause a repaint but not a reflow in a browser rendering process?

   1. top
   2. padding
   3. display
   4. background-color

7. When to Use requestAnimationFrame

   If you want to animate an element’s transform property at 60 frames per second, which approach is best suited for optimal browser performance?

   1. Calling requestAnimationFrame
   2. Using setInteval with 16ms delay
   3. Setting a CSS transition with no duration
   4. Animating with inline CSS only

8. Efficient DOM Updates

   Which strategy helps reduce browser reflows when you need to make several changes to the DOM at once?

   1. Batching DOM updates together
   2. Using setTimeout between changes
   3. Adding and removing elements in a loop
   4. Triggering reflow after each change

9. Understanding Paint

   Changing which type of CSS property generally triggers only the paint step, not layout or composite steps, in the browser’s rendering pipeline?

   1. position
   2. width
   3. float
   4. opacity

10. Rendering Pipeline Basics

    In web rendering, which process re-computes element sizes and positions when a change affects document flow?

    1. Transforming
    2. Reflow
    3. Rasterization
    4. Repaint