Large inline JavaScript blocks

Problem Summary

Large inline JavaScript blocks delay page rendering because JavaScript blocks HTML parsing. The browser can’t render anything until all JS is downloaded, parsed, and executed.

Performance Impact

• Render blocking: Nothing displays until JS completes
• Increased TTFB: Large scripts take time to process
• Parser blocking: HTML parsing stops for JS
• Poor LCP: Content appears late

How to Detect

1. PageSpeed Insights: Flags render-blocking resources
2. 
   
3. Chrome DevTools Network: Large inline script blocks
4. Lighthouse: Shows JS execution time

Solutions

1. Move to External Files

<!-- Before --><script>Large code here</script><!-- After --><script src="script.js"></script>

2. Defer JavaScript

<script src="script.js" defer></script>

3>Async JavaScript

<script src="analytics.js" async></script>

4>Minify and Compress

Reduce inline script size.

Further Reading

• Web.dev: Unblockable Requests