Web Development Web Development 4

Question 1

What is CORS and why is it enforced by browsers?

Accepted Answer

A security mechanism that restricts cross-origin HTTP requests made from scripts

Answer

CORS (Cross-Origin Resource Sharing) is a browser security policy that blocks scripts from making requests to a different origin unless the server explicitly allows it.

Question 2

In JavaScript, what is the output of: typeof null?

Accepted Answer

'object'

Answer

typeof null returns 'object' — a well-known historical bug in JavaScript that has been kept for backward compatibility.

Question 3

Which web performance metric measures the time until a page's main content is visually rendered?

Accepted Answer

Largest Contentful Paint (LCP)

Answer

LCP measures how long it takes for the largest visible content element (image or text block) to fully render in the viewport.

Question 4

What does the CSS 'box-sizing: border-box' declaration change?

Accepted Answer

Includes padding and border within the element's declared width and height

Answer

With border-box, padding and border are included inside the element's specified width/height instead of being added on top.

Question 5

In version control with Git, what does 'git rebase' do compared to 'git merge'?

Accepted Answer

Rebase replays commits onto a new base, creating a linear history; merge creates a merge commit

Answer

Git rebase moves commits to a new base commit, producing a cleaner linear history, while merge preserves the branch topology with a merge commit.

Web Development Practice Test

Web Development Practice Test

Web Development Web Development 4