FPSC Past Papers MCQs

FPSC Programmer (BS 17) PMD High Yield 2026  — 350 MCQs  (Page 28 of 35)

Practice FPSC Past Papers MCQs with solved questions from real past exams. These MCQs cover FPSC Programmer (BS 17) PMD High Yield 2026 past papers and are ideal for candidates preparing for competitive exams.

View Tests (30 MCQs each)
What does the HTTP header Cache-Control: no-cache mean?
  • The browser may store the response but must revalidate it with the server before each use
  • The response is cached forever
  • Caching is disabled only for images
  • The browser must never store the response
What is the order of the browser's critical rendering path?
  • Parse HTML into the DOM and CSS into the CSSOM → build the render tree → layout → paint → composite
  • JavaScript → paint → DOM
  • Paint → layout → DOM
  • Layout → DOM → CSSOM → paint
Which change normally triggers a reflow (layout), rather than just a repaint?
  • Changing the background color
  • Changing the text color
  • Changing visibility to hidden
  • Changing an element's width
What is the difference between <script defer> and <script async>?
  • async preserves the order; defer does not
  • They are identical
  • defer runs scripts in document order after the HTML is parsed; async runs each script as soon as it downloads, in any order
  • defer blocks parsing
Is browser JavaScript multithreaded on the main thread?
  • Yes, each function runs on its own thread
  • Only in Chrome
  • No; it runs on a single main thread with an event loop, and Web Workers provide background threads
  • Yes, when async is used
What triggers 'quirks mode' rendering in browsers?
  • Too many images
  • A missing or invalid DOCTYPE declaration
  • Using HTTPS
  • Using CSS Grid
What is a polyfill?
  • An image compression tool
  • A CSS reset
  • Code that implements a missing modern feature in older browsers
  • A browser extension
Which approach is recommended for handling browser differences?
  • Writing separate sites for each browser
  • Blocking unsupported browsers
  • Feature detection (checking whether an API exists) rather than User-Agent sniffing
  • Parsing the User-Agent string
Why must service workers run on HTTPS (except on localhost)?
  • Because HTTP lacks cookies
  • Because they are written in Java
  • To speed up caching
  • They can intercept and modify network requests, so they need a secure origin to prevent tampering