Web Development Performance Optimization 2

Question 1

What does the browser's Critical Rendering Path (CRP) determine?

Accepted Answer

The sequence of steps to convert HTML/CSS/JS into pixels on screen

Answer

The Critical Rendering Path describes the steps the browser takes—DOM, CSSOM, render tree, layout, paint—to display content.

Question 2

Which HTTP header instructs the browser to cache a resource for exactly 1 hour?

Accepted Answer

Cache-Control: max-age=3600

Answer

Cache-Control: max-age=3600 tells the browser the resource is fresh for 3600 seconds (1 hour).

Question 3

What is the primary benefit of using a Content Delivery Network (CDN)?

Accepted Answer

It reduces latency by serving assets from servers geographically closer to users

Answer

CDNs cache and serve static assets from edge nodes nearest the user, reducing round-trip time.

Question 4

Which technique reduces the number of HTTP requests by combining multiple CSS or JS files into one?

Accepted Answer

Bundling

Answer

Bundling merges multiple files into a single file, reducing the number of individual HTTP requests.

Question 5

What does 'tree shaking' accomplish in modern JavaScript build tools?

Accepted Answer

Removes unused exports from the final bundle

Answer

Tree shaking statically analyzes ES module imports and eliminates dead code that is never imported.

Web Development Practice Test