3.7 Defer the loading of non-critical resources

Web Development

Load non-essential assets asynchronously or with prioritization to improve rendering performance and avoid visual issues.

Success Criteria

• Asynchronous code:
  Load non-essential external assets asynchronously or defer them to avoid rendering issues such as Flash Of Unstyled Content (FOUC), Flash of Invisible Text (FOIT), or Flash of Faux Text (FOFT).
• Optimized loading:
  Use resource and priority hints to improve loading performance when multiple assets compete for bandwidth or rendering order.

View the Guideline

Tags

AccessibilityPerformanceAssetsJavaScriptCSS