Front End Development Performance & Optimization Flashcards
6 cards from real Front End Development practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Front End Development Performance & Optimization flashcards as text
Which image format offers the best compression for photographs on modern web browsers?
Answer: WebP
WebP provides superior lossless and lossy compression for photos compared to JPEG and PNG, reducing file sizes significantly.
What does 'lazy loading' mean in the context of web performance?
Answer: Deferring the loading of off-screen resources until they are needed
Lazy loading defers the loading of non-critical resources (like below-the-fold images) until they are about to enter the viewport.
What is the purpose of minifying CSS and JavaScript files?
Answer: To reduce file size by removing whitespace and unnecessary characters
Minification removes whitespace, comments, and redundant code to reduce file sizes, resulting in faster download times.
Which HTTP caching header tells the browser how long to cache a resource?
Answer: Cache-Control
The Cache-Control header specifies caching directives, including max-age, which tells browsers how long to store a resource.
What is the benefit of using a Content Delivery Network (CDN) for a US-based website?
Answer: It serves assets from geographically closer servers to reduce latency
A CDN distributes content across multiple servers worldwide, serving files from the closest node to reduce latency and load times.
What does the 'async' attribute on a tag do?
Answer: Downloads the script asynchronously without blocking HTML parsing
The async attribute causes the script to download in parallel with HTML parsing and execute as soon as it's downloaded, without blocking.
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