Rewrite dropdown menu

assets/js/src/Dropdown.js

@@ -0,0 +1,36 @@
+function Dropdown() {
+}
+
+Dropdown.prototype.listen = function() {
+    var self = this;
+
+    $(document).on('click', function() {
+        self.close();
+    });
+
+    $(document).on('click', '.dropdown-menu', function(e) {
+        e.preventDefault();
+        e.stopImmediatePropagation();
+
+        var submenu = $(this).next('ul');
+        var submenuHeight = 240;
+
+        if (! submenu.is(':visible')) {
+            self.close();
+
+            if ($(this).offset().top + submenuHeight > $(window).height()) {
+                submenu.addClass('dropdown-submenu-open dropdown-submenu-top');
+            }
+            else {
+                submenu.addClass('dropdown-submenu-open');
+            }
+        }
+        else {
+            self.close();
+        }
+    });
+};
+
+Dropdown.prototype.close = function() {
+    $('.dropdown-submenu-open').removeClass('dropdown-submenu-open');
+};