Issue 5635 - Implement website-default navbar component

static/js/navbar.js

+/*******************************************************************************
+ * Navbar Component

[juliandoucette, 2017/10/26 15:55:56]

suggest: keyboard and aria functionality from
[examlpe](https://www.w3.org/TR/wai-aria-practices/examples/menubar/menubar-1/menubar-1.html)

+ ******************************************************************************/
+(function()
+{
+  document.addEventListener("DOMContentLoaded", function()
+  {
+
+    function Navbar(navbar)
+    {
+      this.navbar = navbar;
+
+      this.navbar
+          .querySelector(".toggle-navbar-collapse")
+          .addEventListener("click", this._onClick.bind(this), false);

[juliandoucette, 2017/10/26 15:55:56]

suggest: Allow click away to close?

+    }
+
+    Navbar.prototype.toggleCollapse = function()
+    {
+      this.navbar.classList.toggle("expanded");
+    };
+
+    Navbar.prototype._onClick = function()
+    {
+      this.toggleCollapse();
+    };
+
+    var navbars = document.getElementsByClassName("navbar");

[juliandoucette, 2017/10/26 15:55:56]

NIT: separate var and for by one line

+    for (var i = 0; i < navbars.length; i++)
+    {
+      new Navbar(navbars[i]);
+    }
+
+  }, false);
+}());