| Faux headings via CSS | Could Exist | Exists | Could Exist | Exists |
| Faux Links | Exists | Could Exist | Could Exist | Exists |
| Faux Lists | Cannot Exist | Exists | Should Exist | Should Exist |
| Hidden interactive elements | Could Exist | Exists | Could Exist | Exists |
| Hidden tooltip content | Could Exist | Could Exist | Could Exist | Must Exist |
| Illogical table data when linearized | Cannot Exist | Cannot Exist | Cannot Exist | Must Exist |
| Incomplete captions | Cannot Exist | Cannot Exist | Cannot Exist | Must Exist |
| Inconsistent content meaning from CSS positioning changes | Could Exist | Could Exist | Should Exist | Must Exist |
| Incorrect `alt` attribute value | Could Exist | Could Exist | Could Exist | Must Exist |
| Incorrect banner element parent | Cannot Exist | Exists | Could Exist | Exists |
| Incorrect element identifiers (shape/location) | Could Exist | Could Exist | Could Exist | Must Exist |
| Incorrect link styling | Could Exist | Exists | Could Exist | Exists |
| Incorrect link title attribute | Exists | Could Exist | Should Exist | Should Exist |
| Incorrect media element attribute (autoplay) | Could Exist | Exists | Should Exist | Should Exist |
| Incorrect page title | Cannot Exist | Cannot Exist | Cannot Exist | Must Exist |
| Incorrect tab component roles | Cannot Exist | Cannot Exist | Could Exist | Must Exist |
| Incorrect table header & content association | Could Exist | Exists | Could Exist | Exists |
| Incorrect use of orientation lock | Could Exist | Exists | Could Exist | Exists |
| Insufficient color contrast | Could Exist | Exists | Could Exist | Exists |
| Invalid 'alt' attribute value | Exists | Could Exist | Could Exist | Should Exist |
| Invalid `autocomplete` attribute values | Could Exist | Exists | Could Exist | Exists |
| Invalid background image | Cannot Exist | Cannot Exist | Cannot Exist | Must Exist |
| Invalid button/link text | Exists | Could Exist | Could Exist | Should Exist |
| Invalid caption elements in layout tables | Could Exist | Could Exist | Could Exist | Must Exist |
| Invalid device orientation message | Could Exist | Could Exist | Could Exist | Must Exist |
| Invalid element role | Exists | Exists | Could Exist | Exists |
| Invalid element tabindex attribute value | Exists | Could Exist | Could Exist | Exists |
| Invalid image background color contrast | Cannot Exist | Cannot Exist | Could Exist | Must Exist |
| Invalid images of text as headings | Could Exist | Could Exist | Could Exist | Must Exist |
| Invalid interactive element role | Could Exist | Could Exist | Could Exist | Must Exist |
| Invalid interactive elements | Exists | Exists | Could Exist | Should Exist |
| Invalid meta redirect | Exists | Could Exist | Could Exist | Exists |
| Invalid meta refresh | Exists | Exists | Could Exist | Exists |
| Invalid non-text contrast ratio | Could Exist | Could Exist | Should Exist | Must Exist |
| Invalid pre element use for tabular data | Cannot Exist | Cannot Exist | Could Exist | Must Exist |
| Invalid required or error field indicators | Could Exist | Cannot Exist | Should Exist | Must Exist |
| Invalid semantic element role | Exists | Could Exist | Could Exist | Exists |
| Invalid server-side image map use | Cannot Exist | Cannot Exist | Should Exist | Must Exist |
| Invalid table formatting | Exists | Could Exist | Could Exist | Exists |
| Invalid text justification | Could Exist | Could Exist | Should Exist | Must Exist |
| Invalid use of abstract role | Exists | Exists | Could Exist | Exists |
| Invalid use of pseudo content | Could Exist | Could Exist | Could Exist | Must Exist |
| Invalid use of text-decoration | Could Exist | Could Exist | Could Exist | Must Exist |
| Invalid use of whitespace for layout | Exists | Could Exist | Could Exist | Exists |
| Invalid use of whitespace within word | Exists | Exists | Could Exist | Exists |
| Invalid visual emphasis through CSS | Could Exist | Exists | Could Exist | Exists |
| Keyboard trap due to multiple content formats | Cannot Exist | Cannot Exist | Should Exist | Must Exist |
| Malformed dl elements | Could Exist | Exists | Could Exist | Exists |
| Malformed dt/dd elements | Could Exist | Exists | Could Exist | Exists |
| Malformed image markup for decorative images | Exists | Cannot Exist | Could Exist | Must Exist |
| Malformed layout tables | Could Exist | Could Exist | Could Exist | Must Exist |
| Malformed list element | Could Exist | Exists | Could Exist | Exists |
| Malformed structural markup | Could Exist | Could Exist | Could Exist | Must Exist |
| Malformed table elements | Could Exist | Could Exist | Could Exist | Must Exist |
| Malformed table header markup | Could Exist | Exists | Could Exist | Exists |
| Misplaced complementary landmark | Cannot Exist | Exists | Could Exist | Exists |
| Misplaced contentinfo landmark element | Cannot Exist | Exists | Could Exist | Exists |
| Misplaced main element | Cannot Exist | Exists | Could Exist | Exists |
| Missing `alt` attribute in `area` element | Exists | Could Exist | Could Exist | Exists |
| Missing ASCII art text alternative | Cannot Exist | Cannot Exist | Should Exist | Must Exist |
| Missing bypass block | Could Exist | Exists | Could Exist | Could Exist |
| Missing character entity text alternative | Could Exist | Could Exist | Could Exist | Must Exist |
| Missing character shortcut controls | Could Exist | Cannot Exist | Could Exist | Must Exist |
| Missing color/background-color property specification | Could Exist | Could Exist | Should Exist | Must Exist |
| Missing datepicker keyboard support | Cannot Exist | Cannot Exist | Should Exist | Must Exist |
| Missing dropdown keyboard support | Cannot Exist | Cannot Exist | Should Exist | Must Exist |
| Missing element alt attribute | Exists | Exists | Could Exist | Exists |
| Missing element event handlers | Cannot Exist | Cannot Exist | Should Exist | Must Exist |
| Missing element focus | Cannot Exist | Cannot Exist | Should Exist | Must Exist |
| Missing element focus user control | Cannot Exist | Cannot Exist | Should Exist | Must Exist |
| Missing element pause when blink is used | Cannot Exist | Cannot Exist | Could Exist | Must Exist |
| Missing form control groups | Could Exist | Could Exist | Could Exist | Must Exist |
| Missing form element label | Exists | Exists | Could Exist | Exists |
| Missing H1 element | Cannot Exist | Exists | Could Exist | Exists |
| Missing heading text | Exists | Exists | Could Exist | Could Exist |
| Missing icon scaling on zoom | Cannot Exist | Cannot Exist | Should Exist | Must Exist |
| Missing icon text (ACCNAME) | Could Exist | Could Exist | Could Exist | Must Exist |
| Missing iframe element title | Exists | Exists | Could Exist | Exists |
| Missing iframe title uniqueness | Could Exist | Exists | Could Exist | Exists |
| Missing image dynamic alt attribute | Could Exist | Cannot Exist | Should Exist | Must Exist |
| Missing input character count availability | Cannot Exist | Cannot Exist | Should Exist | Must Exist |
| Missing input element required attribute | Could Exist | Could Exist | Could Exist | Must Exist |
| Missing interactive element focus | Could Exist | Could Exist | Should Exist | Must Exist |
| Missing interactive element keyboard support | Cannot Exist | Could Exist | Should Exist | Must Exist |
| Missing link text (ACCNAME) | Exists | Exists | Could Exist | Exists |
| Missing main element | Cannot Exist | Exists | Could Exist | Exists |
| Missing media element controls | Cannot Exist | Exists | Should Exist | Should Exist |
| Missing media queries with viewport unit use | Could Exist | Could Exist | Could Exist | Must Exist |
| Missing modal keyboard support | Cannot Exist | Could Exist | Should Exist | Must Exist |
| Missing non-conforming alternative | Cannot Exist | Could Exist | Could Exist | Must Exist |
| Missing page title | Exists | Exists | Could Exist | Could Exist |
| Missing scrollable content keyboard support | Cannot Exist | Cannot Exist | Should Exist | Must Exist |
| Missing search result announcements | Cannot Exist | Cannot Exist | Could Exist | Must Exist |
| Missing select element label (ACCNAME) | Exists | Exists | Could Exist | Exists |
| Missing synchronized media captions | Cannot Exist | Cannot Exist | Cannot Exist | Must Exist |
| Missing synchronized media text alternatives | Cannot Exist | Cannot Exist | Cannot Exist | Must Exist |
| Missing tab element keyboard support | Cannot Exist | Could Exist | Should Exist | Must Exist |
| Missing table element captions | Cannot Exist | Exists | Could Exist | Exists |
| Missing table header text | Could Exist | Could Exist | Could Exist | Must Exist |
| Missing text form control resizing support | Cannot Exist | Cannot Exist | Should Exist | Must Exist |
| Missing unique landmark element titles | Exists | Exists | Could Exist | Exists |
| Multiple banner landmarks exist | Cannot Exist | Exists | Could Exist | Exists |
| Multiple contentinfo landmark elements exist | Cannot Exist | Could Exist | Could Exist | Must Exist |
| Multiple H1 elements | Cannot Exist | Could Exist | Could Exist | Must Exist |
| Multiple input field labels | Exists | Exists | Could Exist | Exists |
| Multiple main landmark elements exist | Cannot Exist | Exists | Could Exist | Exists |
| Nested interactive elements | Exists | Exists | Could Exist | Exists |
| Non-unique landmark elements | Exists | Exists | Could Exist | Exists |
| Obscured text when resized | Cannot Exist | Cannot Exist | Should Exist | Must Exist |
| Obscured text when spacing is adjusted | Cannot Exist | Cannot Exist | Should Exist | Must Exist |
| Obsolete `blink` element use | Exists | Could Exist | Could Exist | Exists |
| Overlapped elements when zoom is used | Cannot Exist | Cannot Exist | Should Exist | Must Exist |
| Reflow & Disappearing Content | Cannot Exist | Cannot Exist | Should Exist | Must Exist |
| Truncated text on zoom | Cannot Exist | Cannot Exist | Should Exist | Must Exist |
| Unequal non-text content descriptions | Cannot Exist | Cannot Exist | Could Exist | Must Exist |
| Unusable hoverable content | Cannot Exist | Cannot Exist | Should Exist | Must Exist |
| Use of obsolete elements | Exists | Exists | Could Exist | Exists |