Explore essential concepts in auditing web pages using Lighthouse within Chrome DevTools, covering performance metrics, accessibility best practices, reporting features, and recommended actions to optimize web experiences. This quiz is designed to assess your understanding of web audit workflows, diagnostic features, and practical use of Lighthouse in professional web development environments.
Which category is NOT assessed during a standard Lighthouse web page audit through Chrome DevTools?
Explanation: Lighthouse audits typically include categories such as Performance, Accessibility, Best Practices, SEO, and sometimes Progressive Web App. Social Media Integration is not a standard audit category offered by Lighthouse. While Performance checks loading efficiency, Accessibility evaluates usability for everyone, and Best Practices ensures common coding standards, Social Media Integration is unrelated and not currently a focus of Lighthouse reports.
When Lighthouse identifies that a page is not efficiently serving images, which 'Opportunities' recommendation is it most likely to display?
Explanation: If images are not optimized, Lighthouse suggests 'Efficiently encode images' under the Opportunities section to enhance performance. 'Reduce CSS complexity' might affect maintainability but is rarely flagged as a key performance opportunity. 'Increase font sizes' is generally related to accessibility, and 'Add alternative text' also belongs to accessibility improvements rather than performance.
While configuring a Lighthouse audit, which simulation mode may developers use to mimic slower network and device conditions?
Explanation: Throttling allows developers to simulate slower networks and CPUs, helping assess how site performance might be impacted under less ideal user conditions. 'Boost Rendering' is not a recognized simulation mode in Lighthouse. 'Quick Scan' and 'Express Mode' are misleading terms and do not reflect any actual feature or mode in the tool.
In a Lighthouse report, which metric specifically measures how quickly the largest visible content element loads on the page?
Explanation: Largest Contentful Paint measures the render time of the largest content element, providing a clear indication of perceived load speed. 'First Input Delay' focuses on the time before a page responds to user interaction. 'Cumulative Layout Shift' measures visual stability, while 'Total Blocking Time' looks at the amount of time the main thread is blocked. Only 'Largest Contentful Paint' directly answers the question.
After running an audit in Lighthouse, which of the following file formats is available for exporting the results for sharing or analysis?
Explanation: Lighthouse results can be exported as a JSON file, allowing detailed programmatic analysis or sharing of audit data. PNG and DOCX are not standard supported formats for exporting Lighthouse audit results. SQL is a database format and not relevant for audit exports. The JSON format preserves all report details and is designed for compatibility across platforms.