Tables Screen reader compatibility

Screen reader compatibility for HTML tables, showing how failures and techniques work in specific screen reader / browser combinations.

The results include two types of test:

• Expected to work - these tests show support when accessibility features are used correctly
• Expected to fail - these tests show what happens when accessibility features are used incorrectly (marked with )

Note: Screen readers attempt to detect layout tables using heuristics, which vary widely between screen readers. When a layout table is detected, a screen reader linearizes the cells into a series of paragraphs, which prevents the table data being understood as a grid. This causes serious problems when a data table is wrongly identified as a layout table. For example, consider trying to understand the Periodic Table of the Elements as a long series of element names without the columns.

Reliability by user agent

The solid area in the graph shows percentage of tests that pass in all tested interaction modes. The cross hatched area shows partial passes that only work in some interaction modes.

An example of a partial pass is when form labels are read when tabbing, but ignored in browse mode.

The average includes all versions, but some browser/AT combinations have tests for multiple versions (NVDA / JAWS / VoiceOver), while others only have tests for a single version (SaToGo and Dolphin).

Reliability trend

Expected to work

These tests use conformant HTML or WCAG sufficient techniques and might be expected to work in screen readers. This doesn't always happen.

Screen Reader	NVDA			JAWS			VoiceOver
Browser	Edge	FF	Cr	Edge	FF	Cr	Mac	iOS
Data table with caption and th
Data table with role=columnheader headers but no th
Data table with role=grid
Data table with role=table
Data table with summary and th
Data table with td headers attribute
Data table with th scope on cell headers
Data table with th cell headers
Layout table with role=presentation
Layout table with single cell

Expected to fail

These tests use non-conformant HTML or WCAG failures and are expected to fail in screen readers.

Screen Reader	NVDA			JAWS			VoiceOver
Browser	Edge	FF	Cr	Edge	FF	Cr	Mac	iOS
Data table th cell headers with no scope
Data table with caption but no th
Data table with role=note
Data table with role=presentation
Data table with summary but no th
Data table with thead, tfoot but no th
Data table with no th elements
Data table with null summary and no th

Key

Tests expected to fail (due to authoring errors) are marked with .

• Works in 100% of tested screen readers
• Fails in 1% - 25% of tested screen readers
• Fails in 26% - 50% of tested screen readers
• Fails in 51% - 75% of tested screen readers
• Fails in 76% - 100% of tested screen readers

• Stable - works, or doesn't cause problems, in all versions of a specific combination of screen reader and browser
• Better - works, or doesn't cause problems, in the most recent version of a specific combination of screen reader and browser (improvement)
• Worse - causes problems in the most recent version of a specific combination of screen reader and browser, but used to work in older versions (regression)
• Broken - causes problems in all versions of a specific combination of screen reader and browser

Test notes

All tests were carried out with screen reader factory settings. JAWS in particular has a wide variety of settings controlling exactly what gets spoken.

Screen readers allow users to interact in different modes, and can produce very different results in each mode. The modes used in these tests are:

• Reading Content read using the “read next” command in a screen reader
• Tabbing Content read using the “tab” key in a screen reader
• Heading Content read using the “next heading” key in a screen reader
• Touch Content read when touching an area of screen on a mobile device

In the “What the user hears” column:

• Commas represent short pauses in screen reader voicing
• Full Stops represent places where voicing stops, and the “read next” or “tab” or “next heading” command is pressed again
• Ellipsis … represent a long pause in voicing
• (Brackets) represent voicing that requires a keystroke to hear