Disallow <hgroup> | The hgroup element should not be used because no assistive technology supports it. | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ | ❌ | ❌ | ❌ |
Must not duplicate ID | Be able to avoid problems in assistive technologies from the viewpoint of machine readability. | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ✅ | ❌ | ❌ | ❌ |
Disallow autofocus attr | | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ | ❌ | ❌ | ❌ |
tabindex attr only -1 or 0 | | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ | ❌ | ❌ | ❌ |
<label> should have control | | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ | ❌ | ❌ | ❌ |
Use landmark | | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ | ❌ | ❌ | ❌ |
No refer to no existent ID | | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ✅ | ❌ | ❌ | ❌ |
Require accessible name | | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ | ❌ | ❌ | ❌ |
Require <h1> | | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ | ❌ | ❌ | ❌ |
Use <ul> | | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ | ❌ | ❌ | ❌ |
Conform to WAI-ARIA | | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ | ❌ | ❌ | ❌ |
Require <html lang> | | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ | ❌ | ❌ | ❌ |
Require <abbr title> | | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ | ❌ | ❌ | ❌ |
Require <track> | | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ | ❌ | ❌ | ❌ |
Require <video muted> | | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ | ❌ | ❌ | ❌ |
No merge cells | | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ | ❌ | ❌ | ❌ |
<summary> no contains interactive contents | There is a case where an assistive technology can't access contents, or contents don't propagate a mouse event to <summary> . | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ | ❌ | ❌ | ❌ |
No duplicate attr | The parser ignores all such duplicate occurrences of the attribute. | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ | ✅ | ❌ | ❌ | ❌ |
Use character reference | | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ | ✅ | ❌ | ❌ | ❌ |
No use deprecated attr | You should not use deprecated attributes from the viewpoint of compatibility. | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ | ✅ | ❌ | ❌ | ❌ |
No use deprecated element | You should not use deprecated elements from the viewpoint of compatibility. | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ | ✅ | ❌ | ❌ | ❌ |
Require doctype | It has the effect of avoiding quirks mode. | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ | ✅ | ❌ | ❌ | ❌ |
No use ineffective attr | | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ | ✅ | ❌ | ❌ | ❌ |
Allow only permitted contents | | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ | ✅ | ❌ | ❌ | ❌ |
Require the datetime attribute if the content of the time element is invalid | | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ | ✅ | ❌ | ❌ | ❌ |
Specify required attr | | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ | ✅ | ❌ | ❌ | ❌ |
Specify charset=UTF-8 | | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ | ✅ | ❌ | ❌ | ❌ |
No use <small> as subheadings | Should not use it in <h1> , <h2> , <h3> , <h4> , <h5> , and <h6> . | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ | ✅ | ❌ | ❌ | ❌ |
No use <caption> within <figure> | When <table> is the only content in <figure> other than <figcaption> , <caption> should be omitted in favor of <figcaption> . | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ | ✅ | ❌ | ❌ | ❌ |
Require charset=UTF-8 | | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ | ❌ | ✅ | ❌ | ❌ |
Require defer attr | Should load and parse scripts lazily to avoid render-blocking. | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ | ❌ | ✅ | ❌ | ❌ |
Require aspect-ratio | Require width and height attr with <img> to avoid Cumulative Layout Shift | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ | ❌ | ✅ | ❌ | ❌ |
Require async decoding image | Require decoding=async with <img> to avoid render-blocking. | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ | ❌ | ✅ | ❌ | ❌ |
Require loading <iframe> lazily | Require loading=lazy with <iframe> to avoid render-blocking that causes loading if its element is out of the viewport. | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ | ❌ | ✅ | ❌ | ❌ |
Allow property attr with <meta> | Be able to use Open-Graph etc. | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ | ❌ | ❌ | ✅ | ❌ |
No hard coding ID | The component that hard-coded ID cannot mount to an app duplicated because the IDs must be unique in a document. Recommend to specify dynamic IDs to avoid doing that. | ❌ | ✅ | ✅ | ❌ | ✅ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ |
No omit end-tag | Recommend to write an end-tag always because it is too difficult for a human decide an element is end-tag omittable. | ❌ | ❌ | ❌ | ✅ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ |
Require noreferrer with target=_blank | Require rel=noreferrer with an element that has target=_blank to prevent leaking referrer information and to block operating referrer documents. | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ | ❌ | ❌ | ❌ | ✅ |