1 files changed, 100 insertions, 0 deletions
diff --git a/js/dropdown.js b/js/dropdown.js
new file mode 100644
index 000000000..32ce4696f
--- /dev/null
+++ b/js/dropdown.js
@@ -0,0 +1,100 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This Source Code Form is "Incompatible With Secondary Licenses", as
+ * defined by the Mozilla Public License, v. 2.0. */
+
+$(function() {
+    'use strict';
+
+    $(window).click(function(e) {
+        // clicking dropdown button opens or closes the dropdown content
+        if (!$(e.target).hasClass('dropdown-button')) {
+            $('.dropdown-button').each(function() {
+                toggleDropDown(e, $(this), $('#' + $(this).attr('aria-controls')), 1);
+            });
+        }
+    }).keydown(function(e) {
+        // Escape key hides the dropdown if visible
+        if (e.keyCode == 27) {
+            $('.dropdown-button').each(function() {
+                var $button = $(this);
+                if ($button.siblings('.dropdown-content').is(':visible')) {
+                    toggleDropDown(e, $button, $('#' + $button.attr('aria-controls')), 1);
+                    $button.focus();
+                }
+            });
+        }
+        // allow arrow up and down keys to choose one of the dropdown items if menu visible
+        if (e.keyCode == 38 || e.keyCode == 40) {
+            $('.dropdown-content').each(function() {
+                var $content = $(this);
+                if ($content.is(':visible')) {
+                    e.preventDefault();
+                    e.stopPropagation();
+                    var $items = $content.find('[role="menuitem"]');
+                    // if none focused select the first or last
+                    var $any_focused = $items.filter(':focus');
+                    if ($any_focused.length == 0) {
+                        var index = e.keyCode == 40 ? 0 : $items.length - 1;
+                        var $link = $items.eq(index);
+                        $link.addClass('active').focus();
+                        return;
+                    }
+                    // otherwise move up or down the list based on arrow key pressed
+                    var inc  = e.keyCode == 40 ? 1 : -1;
+                    var move = $items.index($any_focused) + inc;
+                    var $link = $items.eq(move % $items.length);
+                    $content.find('a').removeClass('active');
+                    $link.addClass('active').focus();
+                }
+            });
+        }
+
+        // enter clicks on a link
+        if (e.keyCode == 13) {
+            $('.dropdown-content:visible a.active').trigger('click');
+        }
+    });
+
+    $('.dropdown-content a').hover(
+        function(){ $(this).addClass('active')  },
+        function(){ $(this).removeClass('active')  }
+    );
+
+    $('.dropdown').each(function() {
+        var $div     = $(this);
+        var $button  = $div.find('.dropdown-button');
+        var $content = $div.find('.dropdown-content');
+        $button.click(function(e) {
+            toggleDropDown(e, $button, $content);
+        }).keydown(function(e) {
+            // allow enter to toggle menu
+            if (e.keyCode == 13) {
+                toggleDropDown(e, $button, $content);
+            }
+        });
+    });
+
+    function toggleDropDown(e, $button, $content, hide_only) {
+        // hide other expanded dropdown menu if any
+        var $expanded = $('.dropdown-button[aria-expanded="true"]');
+        if ($expanded.length && !$expanded.is($button)) {
+            $('#' + $expanded.attr('aria-controls')).hide();
+            $expanded.attr('aria-expanded', false);
+        }
+
+        // clear all active links
+        $content.find('a').removeClass('active');
+        if ($content.is(':visible')) {
+            $content.hide();
+            $button.attr('aria-expanded', false);
+        }
+        // if not using Escape or clicking outside the dropdown div, then we are hiding
+        else if (!hide_only) {
+            $content.show();
+            $button.attr('aria-expanded', true);
+        }
+    }
+});