gistfile1.js

$(document).ready(function() {
  // add a hash to the URL when the user clicks on a tab
  $('a[data-toggle="tab"]').on('click', function(e) {
    history.pushState(null, null, $(this).attr('href'));
  });
  // navigate to a tab when the history changes
  window.addEventListener("popstate", function(e) {
    var activeTab = $('[href=' + location.hash + ']');
    if (activeTab.length) {
      activeTab.tab('show');
    } else {
      $('.nav-tabs a:first').tab('show');
    }
  });
});

I was having trouble with this gist not reverting to a tab with no hash (the first/default tab). I got it working by changing line 9 to read:

if (location.hash.length){

The way it is in the gist, activeTab.length is always 1 as activeTab is a list with one object in it so it never makes it into the else block.

I realize this is a year old now and things may have changed since then, just trying to help out fellow googlers in the future.