Kilotest: Diagnoses of element unknown violation by HTML element 250 on Mozilla Foundation page

Basics

About the page

• URL: https://www.mozilla.org/en-US/
• Tested 32 days ago on 2026-09-08 at 04:02 by job 260908T0359-xmh
• Summary of results:
  • Rule engines:
    • Called: 12
    • Were able to test: 12
    • Reported any rule violations: 11
  • Violations: 753
  • Violators: 192
  • Issues: 47
• Download the full technical report (JSON)

About the issue

• Why it matters: Page includes an unknown element that the browser cannot process
• Priority: highest
• Related WCAG standard: 4.1
• Reported by 1 rule engine (Html Checker API)
• Violations: 1
• Violators: 1

About the violator

• Tag name: BLINK
• Text: Products … About us
• Start tag: <blink class="spacer-gif">
• XPath: /html/body/nav[1]/div[1]/div[1]/blink[1]
• Bounding box: x = 1548, y = 16, width = 100, height = 0
• Reported by Html Checker API

Diagnoses

Here is how rule engines diagnose the element unknown issue for HTML element 250 of the Mozilla Foundation page.

1. The blink element is a completely-unknown element that is not allowed anywhere in any HTML content.

   Rule engine: Html Checker API (World Wide Web Consortium)