Which of the following is a feature enabled by the Service Worker API?

Which of the following is a feature enabled by the Service Worker API?

Answer

•  Enabling a Progressive Web App to run JavaScript files more efficiently
•  Enabling a Progressive Web App to access most common mobile OS services, such as volume controls, screen brightness, and voice recording
•  Enabling a Progressive Web App to synchronize with the server and send push messages in the background
•  Enabling a Progressive Web App to run asynchronously with other Progressive Web Apps

How do you redesign your site to incorporate mobile user experience design principles?

How do you redesign your site to incorporate mobile user experience design principles?

Answer

•  Increase homepage navigation complexity.
•  Hide certain usability features, such as a search bar.
•  Streamline conversion flow.
•  Provide full-screen, brightly colored imagery.

Which term describes the stage in which the browser relates interpreted HTML and CSS documents to display a webpage?

Which term describes the stage in which the browser relates interpreted HTML and CSS documents to display a webpage?

Answer

•  The render tree
•  The CSS Object Model (CSSOM)
•  The Document Object Model (DOM)
•  Parsing

A webpage appears to hang for several seconds before anything appears on screen. Which of the following steps is likely to help reduce load times?

A webpage appears to hang for several seconds before anything appears on screen. Which of the following steps is likely to help reduce load times?

Answer

•  Place image and script files close together in the HTML.
•  Elimate any use of JavaScript to "lazy load" files.
•  Disable Chrome Developer Tools, as the software can create slowdown in the critical rendering path.
•  Set inessential script files to load after the page body.

What kinds of images are resolution- and scale-independent?

What kinds of images are resolution- and scale-independent?

Answer

•  Vector images
•  Raster images
•  Large images
•  JPG images

A webpage with several menu animations performs poorly, even on the latest mobile phone. Which of the following is a likely cause of the slowdown?

A webpage with several menu animations performs poorly, even on the latest mobile phone. Which of the following is a likely cause of the slowdown?

Answer

•  The animations force the browser to recalculate (or reflow) layout.
•  The menu occupies a percentage, rather than fixed width, of the screen.
•  Several CSS font styles have been applied to the menu text.
•  Menu animations that are fluid in portrait mode slow down in landscape mode.

What tool can you use to measure mobile website performance on a desktop computer?

What tool can you use to measure mobile website performance on a desktop computer?

Answer

•  Android emulator
•  Speed Index
•  Scalable vector graphics
•  Chrome Developer Tools