JavaScript SEO: những lỗi phổ biến khiến Google không index được content?

JS SEO có 4 loại lỗi phổ biến khiến Google không index được content — rendering, meta tags, links, và resources.

Lỗi rendering:

1. Content trong useEffect/componentDidMount — Google có thể không chờ async data fetch
2. Client-only routing (React Router) không có SSR fallback — Google thấy blank page
3. Error boundaries catch lỗi nhưng render fallback UI — Google index error message thay vì content

Lỗi meta tags:

1. Dynamic title/description set bằng JS — Google có thể lấy title trước khi JS chạy
2. Thiếu canonical cho dynamic routes

Lỗi links:

1. Navigation bằng onClick + router.push thay vì <a href> — Google không follow JS click events
2. Infinite scroll không có pagination fallback

Lỗi resources:

1. robots.txt block JS/CSS bundles — Google không render được trang
2. Bundle quá lớn khiến Googlebot timeout (>5s)

Fix chung: dùng SSR/SSG, test bằng Google Search Console URL Inspection, dùng <Link> component cho navigation.

JS SEO has 4 common mistake categories that prevent Google from indexing content — rendering, meta tags, links, and resources.

Rendering issues:

1. Content inside useEffect/componentDidMount — Google may not wait for async data fetching
2. Client-only routing (React Router) without SSR fallback — Google sees a blank page
3. Error boundaries catching errors and rendering fallback UI — Google indexes the error message instead of real content

Meta tag issues:

1. Dynamic title/description set via JS — Google may capture the title before JS executes
2. Missing canonicals for dynamic routes

Link issues:

1. Navigation using onClick + router.push instead of <a href> — Google does not follow JS click events
2. Infinite scroll without a pagination fallback

Resource issues:

1. robots.txt blocking JS/CSS bundles — Google cannot render the page
2. Oversized bundles causing Googlebot to time out (>5s)

General fixes: use SSR/SSG, test with Google Search Console URL Inspection, use a <Link> component for all navigation.