Uncategorized @en

How many times per second do most devices refresh their screens?

60

100

20

35

Explanation:

Most devices today refresh their screens 60 times a second. If there’s an animation or transition running, or the user is scrolling the pages, the browser needs to match the device’s refresh rate and put up 1 new picture, or frame, for each of those screen refreshes.

Each of those frames has a budget of just over 16ms (1 second / 60 = 16.66ms). In reality, however, the browser has housekeeping work to do, so all of your work needs to be completed inside 10ms. When you fail to meet this budget the frame rate drops, and the content judders on screen. This is often referred to as jank, and it negatively impacts the user’s experience.

Read more here: https://developers.google.com/web/fundamentals/performance/rendering/

What does “Variant A” in A/B Testing usually represent?

Test version of the web page that is modified from the original

Original version of the web page

Explanation:

Variant A is the original. Variants B through n each contain one or more elements that are modified from the original.

Read more here: https://support.google.com/partners/answer/7336695

Which most accurately describes the purpose of compression?

Minimizing file size

Fitting more into the cache

Making the code faster

Combining files

Explanation:

The process of reducing the size of data is data compression.

Read more here: https://support.google.com/partners/answer/7336590

What is a tool that you can use to emulate and simulate a site that’s experiencing poor or unreliable connectivity?

Webpagetest.org

Speedtest.net

Speedguide.net

Pingdom.com

Explanation:

WebPagetest is an online service that enables a set of performance tests to be run for your site using a variety of networks and host locations. For example, you can try out your site from a server in India on a 2G network, or over cable from a city in the US.

Read more here: https://support.google.com/partners/answer/7336589

Which of the following describes an App shell?

It discourages caching of content that overlaps across pages of the website

It provides a fast first impression gracefully transitioning to a fully loaded page

None

It comprises of all page elements which are dependant of the specific page contents

Explanation:

An application shell is the minimal HTML, CSS, and JavaScript powering a user interface. The application shell should:

• Load fast
• Be cached
• Dynamically display content

Read more here: https://support.google.com/partners/answer/7336597