Tables Screen reader compatibility

Accessibility

Nov 26, 2024

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

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.

Combo	Versions	Reliability	Test Changes
JAWS Chrome	JAWS 2024.2409.2 with Chrome 131	100%
JAWS Edge	JAWS 2024.2409.2 with Edge 131	100%
JAWS Firefox	JAWS 2024.2409.2 with FF 128	80%	2 better
JAWS IE	JAWS 2019.1912.1 with IE11	100%	4 better
NVDA Chrome	NVDA 2024.4 with Chrome 131	100%
NVDA Edge	NVDA 2024.4 with Edge 131	100%
NVDA Firefox	NVDA 2024.4 with FF 128	100%	1 better
NVDA IE	NVDA 2019.2 with IE11	60%
VoiceOver Mac	VoiceOver macOS 14.6 with Safari 17.6	80%	2 better
VoiceOver iOS	VoiceOver iOS 17.7 with Safari iOS 17.7	60%	3 better
WindowEyes IE	WindowEyes 9.2 with IE11	100%	1 better
Dolphin IE	Dolphin SR 15.05 with IE11	100%
SaToGo IE	SaToGo 3.4.96.0 with IE11	100%
Average	Including older versions	79%

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

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