JavaScript SEO

The practice of ensuring JavaScript-rendered content is crawlable and indexable by search engines.

Google renders JavaScript, but the rendering process is delayed — Googlebot first crawls the HTML, queues JavaScript rendering for later (in a second wave), and then processes the rendered DOM. This delay (often days to weeks for new URLs) means content that only appears after JavaScript execution may be indexed later than static HTML content.

Key JS SEO concerns: links only added via JavaScript may be crawled but with lower priority; content inside SPAs (React, Vue, Angular) may not be visible in the initial HTML; lazy-loaded content below the fold may not be indexed if JavaScript rendering fails; and error states in JS apps can cause Googlebot to see empty pages.

Best practices: use server-side rendering (SSR) or static site generation (SSG) for important content, ensure critical links are in the initial HTML, test pages with the URL Inspection tool in Google Search Console (which shows the rendered HTML), and avoid putting important content behind user interactions (clicks, scrolls).