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Chrome for Developers
  • Docs
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    • Get started
    • Performance audits
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  • New in Chrome
  • Overview
  • Performance
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  • Metrics
    • First Contentful Paint
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    • Total Blocking Time
    • Largest Contentful Paint
    • Cumulative Layout Shift
  • Insights
    • CSS selector costs
    • Document request latency
    • Duplicated JavaScript
    • Font display
    • Forced reflow
    • Improve image delivery
    • INP breakdown
    • Layout shift culprits
    • LCP breakdown
    • LCP request discovery
    • Legacy JavaScript
    • Modern HTTP
    • Network dependency tree
    • Optimize DOM size
    • Optimize viewport for mobile
    • Render-blocking requests
    • 3rd parties
    • Use efficient cache lifetimes
  • Diagnostics
    • Avoid enormous network payloads
    • Avoid non-composited animations
    • Defer offscreen images
    • Ensure the page can be restored from the back/forward cache
    • Keep request counts low and transfer sizes small
    • Lazy load third-party resources with facades
    • Minify CSS
    • Minify JavaScript
    • Minimize main thread work
    • Preload key requests
    • Reduce JavaScript execution time
    • Remove unused CSS
    • User Timing marks and measures
  • Retired Metrics
    • Time to Interactive
    • First Meaningful Paint
    • First CPU Idle
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  • Accessibility
  • Accessibility audit scoring
  • Manual checks
    • Custom controls have ARIA roles
    • Custom controls have associated labels
    • Trapped user focus
    • Interactive controls are keyboard-focusable
    • Interactive elements indicate their purpose and state
    • The page has a logical tab order
    • The user's focus is directed to new content added to the page
    • Offscreen content is hidden from assistive technology
    • HTML5 landmark elements are used to improve navigation
    • Visual order on the page follows DOM order
  • Learn Accessibility
  • Best practices audit
  • General best practices
    • Page lacks the HTML doctype, thus triggering quirks mode
    • Browser errors were logged to the console
    • Displays images with incorrect aspect ratio
    • Charset declaration is missing or occurs too late in the HTML
  • Make your page fast
    • Uses document.write()
    • Use passive listeners to improve scrolling performance
  • Make your page secure
    • Links to cross-origin destinations are unsafe
    • Includes front-end JavaScript libraries with known security vulnerabilities
    • Ensure CSP is effective against XSS attacks
    • Does not use HTTPS
    • Does not redirect HTTP traffic to HTTPS
    • Use a strong HSTS policy
    • Mitigate clickjacking with XFO or CSP
    • Mitigate Dom-Based XSS with Trusted Types
  • Create a good user experience
    • Requests the notification permission on page load
    • Requests the geolocation permission on page load
    • Prevents users from pasting into input fields
  • Avoid deprecated technologies
    • Uses Application Cache
    • Uses deprecated APIs
  • Diagnostic audits
    • Detected JavaScript libraries
    • Baseline Features
  • SEO
  • Help search engines understand your content
    • Document does not have a meta description
    • Links do not have descriptive text
    • Document doesn't have a valid hreflang
    • Document does not have a valid rel=canonical
  • Help search engines crawl and index
    • Page has unsuccessful HTTP status code
    • robots.txt is not valid
    • Document uses plugins
  • Mobile friendly changes
    • Document doesn't use legible font sizes
    • Tap targets are not sized appropriately
  • Manual checks
    • Structured data is valid
  • Agentic browsing
  • Agentic browsing scoring