tabs-automatic.js 3.1 KB

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  1. /*
  2. * This content is licensed according to the W3C Software License at
  3. * https://www.w3.org/Consortium/Legal/2015/copyright-software-and-document
  4. *
  5. * File: tabs-automatic.js
  6. *
  7. * Desc: Tablist widget that implements ARIA Authoring Practices
  8. */
  9. 'use strict';
  10. class TabsAutomatic {
  11. constructor(groupNode) {
  12. this.tablistNode = groupNode;
  13. this.tabs = [];
  14. this.firstTab = null;
  15. this.lastTab = null;
  16. this.tabs = Array.from(this.tablistNode.querySelectorAll('[role=tab]'));
  17. this.tabpanels = [];
  18. for (var i = 0; i < this.tabs.length; i += 1) {
  19. var tab = this.tabs[i];
  20. var tabpanel = document.getElementById(tab.getAttribute('aria-controls'));
  21. tab.tabIndex = -1;
  22. tab.setAttribute('aria-selected', 'false');
  23. this.tabpanels.push(tabpanel);
  24. tab.addEventListener('keydown', this.onKeydown.bind(this));
  25. tab.addEventListener('click', this.onClick.bind(this));
  26. if (!this.firstTab) {
  27. this.firstTab = tab;
  28. }
  29. this.lastTab = tab;
  30. }
  31. this.setSelectedTab(this.firstTab, false);
  32. }
  33. setSelectedTab(currentTab, setFocus) {
  34. if (typeof setFocus !== 'boolean') {
  35. setFocus = true;
  36. }
  37. for (var i = 0; i < this.tabs.length; i += 1) {
  38. var tab = this.tabs[i];
  39. if (currentTab === tab) {
  40. tab.setAttribute('aria-selected', 'true');
  41. tab.removeAttribute('tabindex');
  42. this.tabpanels[i].classList.remove('is-hidden');
  43. if (setFocus) {
  44. tab.focus();
  45. }
  46. } else {
  47. tab.setAttribute('aria-selected', 'false');
  48. tab.tabIndex = -1;
  49. this.tabpanels[i].classList.add('is-hidden');
  50. }
  51. }
  52. }
  53. setSelectedToPreviousTab(currentTab) {
  54. var index;
  55. if (currentTab === this.firstTab) {
  56. this.setSelectedTab(this.lastTab);
  57. } else {
  58. index = this.tabs.indexOf(currentTab);
  59. this.setSelectedTab(this.tabs[index - 1]);
  60. }
  61. }
  62. setSelectedToNextTab(currentTab) {
  63. var index;
  64. if (currentTab === this.lastTab) {
  65. this.setSelectedTab(this.firstTab);
  66. } else {
  67. index = this.tabs.indexOf(currentTab);
  68. this.setSelectedTab(this.tabs[index + 1]);
  69. }
  70. }
  71. /* EVENT HANDLERS */
  72. onKeydown(event) {
  73. var tgt = event.currentTarget,
  74. flag = false;
  75. switch (event.key) {
  76. case 'ArrowLeft':
  77. this.setSelectedToPreviousTab(tgt);
  78. flag = true;
  79. break;
  80. case 'ArrowRight':
  81. this.setSelectedToNextTab(tgt);
  82. flag = true;
  83. break;
  84. case 'Home':
  85. this.setSelectedTab(this.firstTab);
  86. flag = true;
  87. break;
  88. case 'End':
  89. this.setSelectedTab(this.lastTab);
  90. flag = true;
  91. break;
  92. default:
  93. break;
  94. }
  95. if (flag) {
  96. event.stopPropagation();
  97. event.preventDefault();
  98. }
  99. }
  100. onClick(event) {
  101. this.setSelectedTab(event.currentTarget);
  102. }
  103. }
  104. // Initialize tablist
  105. window.addEventListener('load', function () {
  106. var tablists = document.querySelectorAll('[role=tablist].automatic');
  107. for (var i = 0; i < tablists.length; i++) {
  108. new TabsAutomatic(tablists[i]);
  109. }
  110. });