Issue 5635 - Implement website-default navbar component

static/js/navbar.js

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

[juliandoucette, 2017/11/06 12:36:43]

BUG: You can't collapse the navbar if you expanded it while the window was
resized down and then resized back up.

[ire, 2017/11/08 17:14:46]

I can't seem to reproduce this. If the navbar is opened and you resize the
window up, it shows as normal. Could you give me some more information?

[juliandoucette, 2017/11/09 14:34:51]

Just re-tested. This only applied to the table layout. Sorry for the confusion.

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