Kilotest: Diagnoses of box size absolute violation by HTML element 446 on Mozilla Foundation page

Here is how tools diagnose the box size absolute issue for HTML element 446 of the Mozilla Foundation page.

Basics

• About the box size absolute issue
  • Why it matters: User cannot enlarge the content of an item for readability
  • Priority: high
  • Related WCAG standard: 1.4.4
• About the Mozilla Foundation page
  • URL: https://www.mozilla.org/en-US/
  • Tested on 2026-04-03 at 03:56
• About HTML element 446
  • Tag name: SOURCE
  • Text: [not applicable]
  • Start tag: <source media="(max-width: 1311px)" srcset="https://www.mozilla.org/media/img/home/2024/ai-gallery/ventures-mobile-375.e3e5514f8945.jpg 375w,https://www.mozilla.org/media/img/home/2024/ai-gallery/ventures-mobile-720.0e636a424d6e.jpg 720w,https://www.mozilla.org/media/img/home/2024/ai-gallery/ventures-mobile-976.e5c770b56f11.jpg 976w,https://www.mozilla.org/media/img/home/2024/ai-gallery/ventures-mobile-1232.b5e07a981e80.jpg 1232w,https://www.mozilla.org/media/img/home/2024/ai-gallery/ventures-mobile-1450.31519a690661.jpg 1450w" sizes="(min-width: 768px) calc((100vw - 32px) / 2),calc(100vw - 32px)" width="1450" height="723">
  • XPath: /html/body/div[2]/main[1]/section[1]/div[1]/div[1]/div[4]/div[1]/picture[1]/source[1]
  • Bounding box: x = 272, y = 3684, width = 0, height = 0

Diagnoses

1. [failed] The test target `width` attribute uses absolute units.

   Tool: QualWeb (University of Lisbon)

   Rule: QW-BP15