Web Development Web Development 5

Question 1

What is the purpose of a Service Worker in web development?

Accepted Answer

Runs in the background to enable offline caching, push notifications, and background sync

Answer

Service Workers are scripts that run in the background, intercepting network requests to enable offline functionality and progressive web app features.

Question 2

In JavaScript, what is the difference between '==' and '==='?

Accepted Answer

== checks value only with type coercion; === checks both value and type without coercion

Answer

The == operator performs type coercion before comparison, while === requires both the value and the type to be identical.

Question 3

Which attribute makes an HTML form input required before form submission?

Accepted Answer

required

Answer

The required attribute on an input element prevents form submission and shows a browser validation message if the field is empty.

Question 4

What does 'tree shaking' mean in the context of JavaScript bundlers like Webpack or Rollup?

Accepted Answer

Eliminating unused exported code from the final bundle

Answer

Tree shaking analyzes ES module imports and removes code that is exported but never imported anywhere, reducing bundle size.

Question 5

What is the role of the 'alt' attribute on an <img> element?

Accepted Answer

Provides alternative text for screen readers and when the image fails to load

Answer

The alt attribute supplies descriptive text used by screen readers for accessibility and displayed by browsers when an image cannot be loaded.

Web Development Practice Test

Web Development Practice Test

Web Development Web Development 5