CSS & Rendering · AuditJet Glossary
Render-Blocking Resources
CSS and JavaScript files that prevent the browser from rendering any page content until they have been downloaded and processed.
By default, <link rel=stylesheet> and <script> tags without async or defer block the browser's HTML parsing and rendering. Render-blocking resources delay FCP and LCP because the browser waits for them before showing any content. Fixing render-blocking issues involves inlining critical CSS, deferring non-critical CSS, and adding async or defer to non-critical scripts.
Related terms
The time from page navigation start until any text, image, non-white canvas, or SVG is first rendered on the page.
The time from page navigation start until the largest image or text block visible in the viewport has finished rendering.
The minimal set of CSS required to render the above-the-fold content of a page without loading any external stylesheet.
Monitor Render-Blocking continuously
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