duplicate id
Two elements on one page with the same id attribute. Labels, aria-labelledby, aria-describedby and skip links all resolve by id and land on the first match, which is usually the wrong element.
What duplicate id does not show
Invalid HTML that validators tolerate and screen readers do not.
How CrawlCheck measures duplicate id
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 |
|---|---|---|
HOST_DUPLICATE_200 | 6.2% | Canonical URL audit: do tags, redirects and sitemap agree? |
Every code, its rule and its current rate: the dataset page. Scan a site to see which apply to it.
Terms this definition uses
Related terms in Indexing and discovery
Whether a page can be found and kept, separately from whether it can be fetched.
nosnippet · max-snippet · max-image-preview · unavailable_after · noimageindex · index coverage · canonical · noindex · X-Robots-Tag · orphan page · E-E-A-T · E-E-A-T proxies · topical authority · Soft 404 · case consistency · accessibility structure · landmark region · accessible name · skip link · main landmark · alt attribute · form control name · IndexNow · faceted navigation · thin content · duplicate content · near-duplicate · boilerplate · MinHash · shingle · dead anchor · placeholder content · image placeholder · alt text · EXIF
Questions about duplicate id
What is duplicate id?
Two elements on one page with the same id attribute. Labels, aria-labelledby, aria-describedby and skip links all resolve by id and land on the first match, which is usually the wrong element.
What does duplicate id not show or guarantee?
Invalid HTML that validators tolerate and screen readers do not.
How does CrawlCheck measure duplicate id?
Through the finding code HOST_DUPLICATE_200, each with a stated rule, evidence bytes and a live share of scans on the dataset page.
Which area of the glossary does duplicate id belong to?
Indexing and discovery: Whether a page can be found and kept, separately from whether it can be fetched.
← form control name · IndexNow →
See it in the full glossary · 772 terms across 19 areas.
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