render gap
The difference between the text a page serves in its HTML and the text that exists only after JavaScript has run, measured as the share of rendered words absent from the delivered bytes.
What render gap does not show
A crawler that does not execute scripts never sees the gap's contents; measuring it needs a real browser, which is what a browser extension provides.
How CrawlCheck measures render gap
One finding code measures it. Its share of all scans is computed from the live corpus when this page is served, not typed into it.
| Finding code | Share of scans | Guide |
|---|---|---|
CONTENT_NEEDS_JAVASCRIPT | 1.3% | Do AI crawlers and agents render JavaScript? |
Every code, its rule and its current rate: the dataset page. Scan a site to see which apply to it.
Where render gap comes up on this site
- AI visibility tools that grade you 100% and still sell you the fixA render gap is the site withholding content from every machine equally.
Related terms in Measurement and evidence
The vocabulary for saying how strongly something is known.
read equivalence · content-change clock · self-claim ledger · agent task canary · revocation delta · signed verdict · hash-prefix lookup · k-anonymity · publication floor · data snapshot · evidence level · false positive · denominator note · percentile rank · population baseline · cohort asymmetry · self-audit invariant · unscored measurement · dated series · change receipt · regression · finding age · graded through a wall · self-audit · placeholder in record · fetcher disagreement · own-host loop · score version · row review · double-counted defect · cosmetic row · gated row · log file analysis · AI referral attribution · finding fingerprint · finding state · headroom · fix list · lab data · Lighthouse · RUM · LCP · CLS · INP · topicality · intent coverage · canary · citation rate · presence rate · answer stability
Questions about render gap
What is render gap?
The difference between the text a page serves in its HTML and the text that exists only after JavaScript has run, measured as the share of rendered words absent from the delivered bytes.
What does render gap not show or guarantee?
The difference between the text a page serves in its HTML and the text that exists only after JavaScript has run, measured as the share of rendered words absent from the delivered bytes. A crawler that does not execute scripts never sees the gap's contents; measuring it needs a real browser, which is what a browser extension provides.
How does CrawlCheck measure render gap?
Through the finding code CONTENT_NEEDS_JAVASCRIPT, each with a stated rule, evidence bytes and a live share of scans on the dataset page.
Which area of the glossary does render gap belong to?
Measurement and evidence: The vocabulary for saying how strongly something is known.
See it in the full glossary · 731 terms across 19 areas.