Front End Development Technology & Digital Applications 2

Question 1

Which Web API allows front-end code to make HTTP requests to a server and handle responses asynchronously?

Accepted Answer

XMLHttpRequest / Fetch API

Answer

XMLHttpRequest and the modern Fetch API are the standard browser APIs for making asynchronous HTTP requests to servers.

Question 2

What does the browser's 'same-origin policy' restrict?

Accepted Answer

Scripts on one origin accessing resources from a different origin

Answer

The same-origin policy prevents scripts from one origin (scheme+host+port) from reading resources from a different origin without explicit CORS permission.

Question 3

Which storage mechanism stores data with no expiration date and persists even after the browser is closed?

Accepted Answer

localStorage

Answer

localStorage persists data indefinitely across browser sessions until explicitly cleared, unlike sessionStorage which clears on tab close.

Question 4

A Progressive Web App (PWA) uses which technology to enable offline functionality?

Accepted Answer

Service Workers

Answer

Service Workers act as a network proxy, intercepting requests and serving cached responses to enable offline functionality in PWAs.

Question 5

What is the primary purpose of a CDN (Content Delivery Network) in web applications?

Accepted Answer

Serve assets from geographically closer servers to reduce latency

Answer

A CDN distributes static assets across edge servers worldwide so users download files from the nearest server, reducing latency.

Front End Development Practice Test

Front End Development Practice Test

Front End Development Technology & Digital Applications 2