E-Commerce Development Mobile Commerce 4 — Questions and Answers
Question 1: Which technique reduces mobile page weight by sending only the visible portion of a long page and loading the rest as the user scrolls?
- Infinite scroll / lazy loading (Correct answer)
- Pagination with full-page reload
- Server-side rendering of all pages at once
- Edge caching of the full HTML
Correct answer: Infinite scroll / lazy loading
Lazy loading defers off-screen content requests until the user scrolls near them, reducing initial payload and perceived load time.
Question 2: A mobile checkout form auto-fills incorrectly because the browser doesn't recognize the fields. Which HTML attribute fixes this?
- autocomplete (e.g., autocomplete='cc-number') (Correct answer)
- autofill='true'
- name='autofill-card'
- data-fill='browser'
Correct answer: autocomplete (e.g., autocomplete='cc-number')
The autocomplete attribute with standard token values (cc-number, cc-exp, shipping name, etc.) enables browser and password-manager autofill.
Question 3: Which mobile analytics event should an e-commerce developer fire to track when a user views a product detail page?
- view_item (Correct answer)
- page_view_product
- product_open
- pdp_render
Correct answer: view_item
GA4 and most analytics platforms use the view_item event (part of the Enhanced Ecommerce spec) to track product detail page views.
Question 4: What is the recommended minimum touch target size for interactive UI elements on mobile to meet accessibility guidelines?
- 44x44 CSS pixels (Correct answer)
- 16x16 CSS pixels
- 32x32 CSS pixels
- 60x60 CSS pixels
Correct answer: 44x44 CSS pixels
Apple's HIG and Google's Material Design both recommend a minimum 44x44pt / dp touch target to reduce tap errors.
Question 5: Which mobile-first CSS framework approach uses a 'small screens first' default, then adds complexity with min-width breakpoints?
- Mobile-first responsive design (Correct answer)
- Desktop-first responsive design
- Adaptive layout switching
- Device-specific stylesheets
Correct answer: Mobile-first responsive design
Mobile-first CSS writes base styles for small screens and uses min-width media queries to progressively enhance for larger screens.
Question 6: An m-commerce app wants to send a notification to users who left items in the cart. Which technology enables this without requiring the app to be open?
- Web Push Notifications (via Service Worker) (Correct answer)
- WebSockets
- Server-Sent Events
- HTTP long polling
Correct answer: Web Push Notifications (via Service Worker)
Web Push uses a service worker that can receive push messages even when the browser is closed, making cart abandonment nudges possible.
Question 7: Which security measure specifically protects mobile e-commerce API endpoints from being called by unauthorized domains on the web?
- CORS (Cross-Origin Resource Sharing) policy (Correct answer)
- CSRF token only
- Content-Security-Policy header only
- Rate limiting alone
Correct answer: CORS (Cross-Origin Resource Sharing) policy
CORS headers restrict which origins browsers are allowed to make cross-origin API requests to, blocking unauthorized web-based callers.
E-Commerce Development Mobile Commerce 4
Which technique reduces mobile page weight by sending only the visible portion of a long page and loading the rest as the user scrolls?