Issue 5635 - Implement website-default navbar component

static/js/navbar.js

+/*******************************************************************************
+ * Navbar Component
+ ******************************************************************************/
+
+document.addEventListener("DOMContentLoaded", function()
+{
+
+  function Navbar(navbar)
+  {
+    this.navbar = navbar;
+
+    this.navbar
+        .querySelector(".toggle-navbar-collapse button")
+        .addEventListener("click", this._onClick.bind(this), false);
+  }
+
+  Navbar.prototype.toggleCollapse = function()
+  {
+    this.navbar.classList.toggle("expanded");
+  };
+
+  Navbar.prototype._onClick = function()
+  {
+    this.toggleCollapse();
+  };
+
+  var navbars = document.getElementsByClassName("navbar");
+  for (var i = 0; i < navbars.length; i++)
+  {
+    new Navbar(navbars[i]);
+  }
+
+}, false);