How to test a JavaScript website for SEO
Raw HTML and rendered HTML are different views
The raw response is the document a server returns before a browser runs page scripts. The rendered view is the DOM after a controlled Chromium session loads the page. Modern frameworks can put the same search evidence in both views, add it during hydration, or replace it entirely.
This checker measures seven concrete fields in both versions. It labels a difference without deciding that every difference is harmful.
- A title, description, H1, or canonical that appears only after JavaScript depends on rendering.
- Structured data and crawlable links can also be added or removed by client code.
- Large readable-text changes show that much of the page body arrived after the initial response.
When JavaScript can hide important page content
Google can render JavaScript, but crawling and rendering are separate stages and not every crawler has the same capability. A page that exposes its essential identity and links in the initial HTML is easier for a wider set of search, social, directory, and agent systems to understand.
Prioritize the product name, unique page title, primary description, canonical URL, important internal links, and core content. Interactive enhancements can remain client-side without making the page's meaning depend on them.
Confirm the result with Google Search Console
Mydentify fetches the public raw response, then opens the same final URL in a controlled Chromium session with bounded time and requests. The render is not Googlebot, and anti-bot systems or geography rules can produce a different response.
Use Google Search Console URL Inspection for Google's observed render, canonical, and indexing status. Use this comparison to locate what changed and make the next debugging step specific.