Kilotest: Diagnoses of attribute invalid violation by HTML element 291 on Tradeoffs page

Basics

About the Tradeoffs page

• URL: https://tradeoffs.org/
• Tested 30 days ago by job 5g2 on 2026-06-20 at 13:59

About HTML element 291

• Tag name: BUTTON
• Text: Open dropdown menu
• Start tag: <button aria-expanded="false" class="submenu-expand" [class]="setState563 ? 'submenu-expand open-dropdown' : 'submenu-expand'" [aria-expanded]="setState563 ? 'true' : 'false'" on="tap:AMP.setState( { setState563: !setState563 } )" aria-haspopup="true" data-toggle-parent-id="toggle-563" aria-controls="submenu-563">
• XPath: /html/body/div[1]/header[1]/div[1]/div[1]/div[1]/div[1]/nav[1]/ul[1]/li[4]/button[1]
• Bounding box: x = 706, y = 31, width = 24, height = 18

About the attribute invalid issue

• Why it matters: Item behaves improperly
• Priority: highest
• Related WCAG standard: 1.3.1

Diagnoses

Here is how rule engines diagnose the attribute invalid issue for HTML element 291 of the Tradeoffs page.

1. Attribute [class] not allowed on element button at this point.

   Tool: Html Checker API (World Wide Web Consortium)

2. Attribute [aria-expanded] not allowed on element button at this point.

   Tool: Html Checker API (World Wide Web Consortium)

3. Attribute on not allowed on element button at this point.

   Tool: Html Checker API (World Wide Web Consortium)