PERF-009
Inline script uses document.write()
LowDefault severity · Performance · SEO, quality and performance
Last reviewed
What it checks
Inline scripts calling document.write().
Why it matters
document.write blocks the page while it runs and Chrome blocks scripts injected this way on slow connections.
Recommended fix
Insert elements with DOM methods (appendChild) or load third-party tags asynchronously.
How to verify
Run Lighthouse and confirm no "Avoid document.write()" warning.
Example fix prompt
Generic prompt (your report adds the evidence)
Please fix this production issue in my app.
Issue PERF-009: Inline script uses document.write()
Site: https://your-app.example
First confirm the issue in the code or live config. If it is not present, say so and change nothing.
Task: Replace the document.write() calls in the inline scripts with createElement/appendChild, or load the third-party tag with async.
Constraints: make the smallest change that fixes this, keep the current design and behaviour, never paste secret values into code or chat, and tell me which files you changed.
Done when: Run Lighthouse and confirm no "Avoid document.write()" warning.