Add warning for HTML files that one or more HTML elements uses the same id attribute value in a HTML file

[lulunac27a]

Product

axe Linter

Feature Description

HTML elements can only have one id attribute value for the whole HTML file.
For example, the following doesn't meet the requirements:

<div id="content">
  <span id="content">content</span>
</div>

[straker]

Thanks for the issue. Axe-core use to have a rule called duplicate-id that did this, but we deprecated it as just having duplicate id's on the page doesn't cause any accessibility problems. It's only when those id's are used in ARIA attributes that cause problems. As such, I don't think we'll support this in axe-linter for the same reason.