What is JavaScript rendering?
JavaScript rendering means executing JavaScript to build a page’s visible content in the browser. Crawlers that do not execute JavaScript only see the delivered HTML, which is often an almost empty page.
Many modern websites first deliver only a skeleton and load text, prices or product lists via JavaScript. People in a browser do not notice. A crawler that only reads the HTML misses exactly that content.
Google’s documentation describes that Googlebot renders JavaScript, but in a separate step after crawling. For many other crawlers there is no comparable commitment. Whatever is not in the delivered HTML may simply not exist for them.
This creates a render gap: the difference between what a person reads on the page and what a crawler receives without JavaScript. The gap explains some cases where a website is well made and still does not appear in AI answers.
What it means for your website
Open your page with JavaScript disabled, or read the page source instead of the developer tools view. If your key statements, services and contact details are missing there, simple crawlers cannot see them either. The deeploupe render gap report shows how often this happens on small websites, and the paid report compares both versions for your own site.
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Terms help you understand. Whether AI crawlers can reach your site is something you measure.
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