JavaScript SEO
Optimising JavaScript-heavy sites so search engines can properly render and index the content. If Google can't execute your JS, it can't see your content. A growing problem as sites get more complex.
Why It Matters
Modern websites increasingly rely on JavaScript to render content. Single-page applications (React, Vue, Angular), dynamic content loading, and client-side rendering mean that the HTML Google initially downloads might be an empty shell - all the actual content gets rendered by JavaScript.
Google can render JavaScript, but it's resource-intensive and happens in a separate, delayed queue. There's no guarantee Google will render your JS correctly or quickly. Content that depends entirely on client-side JavaScript is at a significant indexing disadvantage.
In Practice
Test how Google sees your JavaScript-rendered pages using the URL Inspection tool in Search Console. Compare the rendered HTML to what users see. If content is missing from the rendered version, Google isn't seeing it.
The safest approach is server-side rendering (SSR) or static site generation (SSG). These deliver fully-rendered HTML to Googlebot, with JavaScript as a progressive enhancement rather than a requirement.
If you must use client-side rendering, implement dynamic rendering as a fallback - serve pre-rendered HTML to crawlers. But treat this as a stopgap, not a permanent solution.
Common Mistakes
Assuming Google renders all JavaScript perfectly. Using JavaScript for critical navigation links. Loading content behind click events or scroll triggers that Googlebot can't activate. Not testing the rendered output in Search Console.
Related Terms
Glossary
Crawling
How search engine bots discover and download your pages - the first step to ranking.
Glossary
Indexing
Adding a crawled page to Google's database so it can appear in search results.
Glossary
Googlebot
Google's web crawler that discovers, downloads, and indexes your pages.
Glossary
Technical SEO
Optimising your site's infrastructure so search engines can crawl, render, and index it.
Glossary
CMS
Content Management System - the software running your website (WordPress, Shopify, etc).
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