JavaScript SEO Checker
See how much of a page is in the raw HTML versus loaded by JavaScript.
About the JavaScript SEO Checker
Modern sites often build pages in the browser with JavaScript frameworks such as React, Vue or Angular. Google can render JavaScript, but it does so in a second wave that can be delayed, and errors can leave content unseen. Most AI crawlers (the bots behind ChatGPT search, Claude, Perplexity and others) and many social and SEO tools do not run JavaScript at all.
This checker looks at the raw HTML a crawler receives before any script runs. If your main text, links, title or canonical are missing there, the page depends on rendering – and you should consider server-side rendering (SSR), static generation or pre-rendering.
Frequently asked questions
Can Google index JavaScript content?
Usually yes, but rendering is resource-intensive and can be delayed. Content in the initial HTML is indexed faster and more reliably.
Do AI search engines run JavaScript?
Most AI crawlers fetch raw HTML only. If your content needs JavaScript to appear, those systems may see an empty page.
What is the best fix?
Server-side rendering or static site generation, which frameworks like Next.js, Nuxt, SvelteKit and Astro support out of the box.