Search engines render JavaScript, but rendering isn't guaranteed to happen perfectly or immediately, which makes JavaScript-heavy sites worth extra scrutiny.
Confirm Content Actually Renders
Content that only appears after a user interaction, like a click or scroll, may never be seen by a crawler at all.
Don't Rely Solely on Client-Side Rendering
Server-side rendering or pre-rendering critical content reduces the risk of indexing delays or incomplete rendering.
Check What a Crawler Actually Sees
Comparing the rendered page to the raw source code reveals gaps between what a browser shows and what gets indexed.
Next step: Use the Webpage Spider View to compare what a crawler sees against what a visitor sees.