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Accessibility conformance

3270Web aims to meet WCAG 2.1 Level AA. This page is the statement of where it stands, what was tested, and what is known not to conform.

It is written to be useful in a procurement review: the claims are scoped, the evidence is named, and the exceptions are stated rather than left for somebody to find.

Conformance claim

3270Web partially conforms to WCAG 2.1 Level AA. "Partially conforms" means some parts of the content do not fully conform; the parts are named under Known issues below.
Standard Web Content Accessibility Guidelines 2.1
Conformance level AA (partial — see Known issues)
Scope The 3270Web browser interface: the connect page, the terminal, every dialog reachable from it, and the account pages under AUTH_MODE=local
Out of scope The content of the host application. See What 3270Web cannot fix
Last reviewed This release

How it was tested

Two passes, because neither alone is worth much.

Automated. axe-core 4.13 against the rulesets wcag2a, wcag2aa, wcag21a and wcag21aa, driven through a real Chromium browser, over eighteen surfaces:

  • the connect page and the connected terminal
  • eleven dialogs — settings, about, connection profiles, find on screen, screen history, keyboard mapping, tasks, file transfer, connection details, logs and disconnect
  • the five account pages that appear under AUTH_MODE=local — first-run setup, sign-in, password change, account administration and the audit log

Dialogs were opened before being scanned, because a hidden dialog is a dialog nothing checks.

Manual. The criteria automation cannot decide:

  • keyboard traversal of every control, watching for a visible focus indicator at each stop
  • the terminal's keyboard-trap escape hatch
  • reflow at 320 CSS pixels
  • text resized to 200%
  • whether status messages are announced
  • whether focus can land on something that cannot be seen

What conforms

Automated testing reports zero WCAG 2.1 A or AA violations across all eighteen surfaces. The manual pass adds:

Keyboard operation (2.1.1, 2.4.3, 2.4.7). Every control is reachable and operable from the keyboard. All 45 tab stops sampled on the terminal page carry a visible focus indicator — an outline or a shadow — with none relying on colour alone.

No keyboard trap (2.1.2). The terminal deliberately takes Tab and Shift+Tab, because those are 3270 field navigation and an operator expects them to move between fields rather than out of the screen. That is exactly the situation 2.1.2 exists for, so there is a documented way out: Ctrl+Tab moves focus to a labelled escape-hatch control immediately after the terminal. Ctrl+Shift+Tab does the same in reverse. See Keyboard and Controls.

Field labelling (1.3.1, 4.1.2). Each input's accessible name is derived from the protected text to its left on the screen itself, so a screen reader announces "Customer number, edit text" rather than "edit text". This is the part worth understanding: a 3270 screen has no markup and no labels — the association between a caption and the field beside it exists only in the character grid, and 3270Web reconstructs it.

Status messages (4.1.3). The operator information area, the run-status panel and the notification toasts are live regions, so a change in keyboard state, a completed step or a failure is announced without moving focus.

Bypass blocks (2.4.1). Every page carries a main landmark. On the terminal, focus starts inside it on page load — the menu bar and session tabs are already behind you. There is deliberately no skip link; see Design decisions.

Resize text (1.4.4). At 200% text, no control is pushed off screen and the page does not scroll horizontally.

Contrast (1.4.3). No text falls below 4.5:1 in the default theme. Seven built-in themes ship, and a custom theme editor allows any palette — a theme of your own making is your own to check.

Reduced motion (2.3.3). Animation is suppressed under prefers-reduced-motion.

Keeping this current

A conformance statement is a measurement, and the thing measured keeps growing: the account pages above did not exist when the first audit ran, and each arrived without a lang attribute or a landmark. So the checks that can be automated are, and they enumerate the templates on disk rather than a list of names — a list only covers the pages somebody remembered to add to it. A new page that ships without them fails the build.

Dialog behaviour

A static scan reads the markup of a dialog; it cannot press Tab. The properties that matter for a dialog are all behavioural, so there is a browser check for them:

ALLOW_SAMPLE_APPS=true go run ./cmd/3270Web    # another terminal
node scripts/check-modals.mjs

It opens every dialog on the terminal screen in turn and asserts that opening one moves focus into it (2.4.3), that Tab stays inside it (2.4.3), that the page behind the backdrop does not scroll, that Escape closes the topmost dialog and only that one, and that closing everything releases the scroll lock again.

These are properties of one shared helper — web/static/modal-utils.js — and that is the point. Each of them had been got wrong at least once by a dialog that arranged its own: a focus trap listening on a dialog that focus was never moved into, so Tab walked into the page behind it; a scroll lock on <body> on a page where <html> is the element that scrolls; and several private Escape listeners that all fired on one keypress, closing a dialog and the one it had been opened from together. A dialog joins the shared stack by calling pushModal when it opens and popModal when it closes, and gets all five.

Known issues

Stated because a conformance claim that lists nothing is not a conformance claim.

A residual horizontal scroll of about 9 pixels at 320 CSS pixels wide (1.4.10). At the narrowest supported width the document reports a scrollable area a few pixels wider than the viewport. No visible content sits in that region — every element renders inside the viewport — so nothing is cut off or unreachable, but a horizontal scrollbar can appear. Being tracked; it is a layout artifact rather than content that requires scrolling to read.

Custom themes are unverified. The default and built-in themes were checked. The theme editor lets an operator choose any foreground and background, including combinations well under 4.5:1. Nothing validates a custom palette's contrast.

The AI chat panel's responses are third-party content. Text returned by a model provider is rendered as it comes. Its structure — headings, lists, tables — is whatever the model produced.

Design decisions

Two choices that look like failures and are not.

The terminal grid scrolls horizontally on a narrow screen, and does not reflow. WCAG 1.4.10 exempts "parts of the content which require two-dimensional layout for usage or meaning". A 3270 screen is the textbook case: which column a character occupies is information — column 40 of row 6 sits under column 40 of row 5, applications draw boxes and columns out of that, and a line that wrapped would be a line that lied. So below tablet width the grid scrolls inside its own region rather than reflowing, and the page around it does not scroll. Use the zoom control in the terminal tools for a size that suits the device: it scales the grid, which keeps it a grid.

There is no skip link. A link at the top of the document could not be reached in practice. Tab and Shift+Tab inside the terminal are 3270 field navigation, and leaving through the Ctrl+Tab escape hatch puts focus after the terminal, not before it — so the link would sit somewhere a keyboard user never arrives. An unreachable skip link is a worse answer than none, so 2.4.1 is met the other two ways WCAG accepts: a main landmark, and focus starting on the main content.

What 3270Web cannot fix

3270Web is a terminal. What it displays is drawn by the host application, and that content's accessibility is the host's, not the terminal's:

  • Colour used alone to convey meaning — if an application marks errors only by drawing a field red, the terminal renders red.
  • Field captions that are not adjacent — label derivation reads the protected text next to a field. An application that puts its caption elsewhere gives nothing to derive from.
  • Timed screens — a host that clears a screen on its own timer is doing so beneath the terminal.

Where a host is the barrier, Guided Business Tasks are often the better answer than making the green screen accessible: a task presents a form with named inputs and a named answer, and never shows the screen at all.

Reporting a problem

Accessibility problems are bugs. Please report them at github.com/3270io/3270Web/issues, with the surface (connect page, terminal, which dialog), what you were using to navigate, and what happened.