Improve accessibility for modules and lang menus

Ever since the contents of the modules and lang menus started
being populated upon click, the flow for screenreader users has
been potentially confusing.

This patch introduces a11y-toggle into the mix:
https://github.com/edenspiekermann/a11y-toggle
Checkboxes were changed into buttons. This hopefully makes it
clear we want the user to click them.

The contents tree still uses the checkbox hack, because its items
are populated upon page load.

Change-Id: I3482bea0c8669f96794498fc37d9d18fe3f829d5
Reviewed-on: https://gerrit.libreoffice.org/72467
Tested-by: Jenkins
Tested-by: Olivier Hallot <olivier.hallot@libreoffice.org>
Reviewed-by: Olivier Hallot <olivier.hallot@libreoffice.org>

1 files changed, 100 insertions, 0 deletions

diff --git a/help3xsl/a11y-toggle.js b/help3xsl/a11y-toggle.js
new file mode 100644
index 0000000000..821a8e0272
--- /dev/null
+++ b/help3xsl/a11y-toggle.js
@@ -0,0 +1,100 @@
+/*
+MIT License
+
+Copyright (c) 2016 Edenspiekermann
+
+*/
+
+(function () {
+  'use strict';
+
+  var internalId = 0;
+  var togglesMap = {};
+  var targetsMap = {};
+
+  function $ (selector, context) {
+    return Array.prototype.slice.call(
+      (context || document).querySelectorAll(selector)
+    );
+  }
+
+  function getClosestToggle (element) {
+    if (element.closest) {
+      return element.closest('[data-a11y-toggle]');
+    }
+
+    while (element) {
+      if (element.nodeType === 1 && element.hasAttribute('data-a11y-toggle')) {
+        return element;
+      }
+
+      element = element.parentNode;
+    }
+
+    return null;
+  }
+
+  function handleToggle (toggle) {
+    var target = toggle && targetsMap[toggle.getAttribute('aria-controls')];
+
+    if (!target) {
+      return false;
+    }
+
+    var toggles = togglesMap['#' + target.id];
+    var isExpanded = target.getAttribute('aria-hidden') === 'false';
+
+    target.setAttribute('aria-hidden', isExpanded);
+    toggles.forEach(function (toggle) {
+      toggle.setAttribute('aria-expanded', !isExpanded);
+    });
+  }
+
+  var initA11yToggle = function (context) {
+    togglesMap = $('[data-a11y-toggle]', context).reduce(function (acc, toggle) {
+      var selector = '#' + toggle.getAttribute('data-a11y-toggle');
+      acc[selector] = acc[selector] || [];
+      acc[selector].push(toggle);
+      return acc;
+    }, togglesMap);
+
+    var targets = Object.keys(togglesMap);
+    targets.length && $(targets).forEach(function (target) {
+      var toggles = togglesMap['#' + target.id];
+      var isExpanded = target.hasAttribute('data-a11y-toggle-open');
+      var labelledby = [];
+
+      toggles.forEach(function (toggle) {
+        toggle.id || toggle.setAttribute('id', 'a11y-toggle-' + internalId++);
+        toggle.setAttribute('aria-controls', target.id);
+        toggle.setAttribute('aria-expanded', isExpanded);
+        labelledby.push(toggle.id);
+      });
+
+      target.setAttribute('aria-hidden', !isExpanded);
+      target.hasAttribute('aria-labelledby') || target.setAttribute('aria-labelledby', labelledby.join(' '));
+
+      targetsMap[target.id] = target;
+    });
+  };
+
+  document.addEventListener('DOMContentLoaded', function () {
+    initA11yToggle();
+  });
+
+  document.addEventListener('click', function (event) {
+    var toggle = getClosestToggle(event.target);
+    handleToggle(toggle);
+  });
+
+  document.addEventListener('keyup', function (event) {
+    if (event.which === 13 || event.which === 32) {
+      var toggle = getClosestToggle(event.target);
+      if (toggle && toggle.getAttribute('role') === 'button') {
+        handleToggle(toggle);
+      }
+    }
+  });
+
+  window && (window.a11yToggle = initA11yToggle);
+})();