diff -u b/misc/ajax_facets.js b/misc/ajax_facets.js
--- b/misc/ajax_facets.js
+++ b/misc/ajax_facets.js
@@ -357,7 +357,7 @@
     var ajax = new Drupal.ajax(false, false, settings);
     ajax.success = function(response, status) {
       // Push new state only on successful ajax response.
-      if (typeof history.pushState != "undefined" && pushStateNeeded) {
+      if (pushStateNeeded) {
         var stateUrl = Drupal.settings.basePath + Drupal.settings.pathPrefix + Drupal.settings.facetapi.searchPath + '?' + Drupal.ajax_facets.getFacetsQuery(),
           state = {
             current_id: Drupal.ajax_facets.current_id,
@@ -365,7 +365,7 @@
             facets: Drupal.ajax_facets.queryState['f']
           };
 
-        history.pushState(state, document.title, stateUrl);
+        History.pushState(state, document.title, stateUrl);
       }
 
       //Pass back to original method.
@@ -531,7 +531,7 @@
   Drupal.ajax_facets.initHistoryState = function ($facet) {
     // Set the initial state only initial page load.
     if (typeof history.replaceState != "undefined" && Drupal.ajax_facets.firstLoad) {
-      history.replaceState({
+      History.replaceState({
         current_id: $facet.attr('id'),
         current_facet_name: $facet.data('facet'),
         facets: Drupal.ajax_facets.queryState['f']
@@ -545,8 +545,8 @@
    */
-  window.onpopstate = function (event) {
-    if (event.state != null) {
-      Drupal.ajax_facets.queryState['f'] = event.state.facets;
-      Drupal.ajax_facets.sendAjaxQuery($('#' + event.state.current_id), false);
-    }
-  };
+  History.Adapter.bind(window, 'statechange', function() {
+    var state = History.getState();
+
+    Drupal.ajax_facets.queryState['f'] = state.data.facets;
+    Drupal.ajax_facets.sendAjaxQuery($('#' + state.data.current_id), false);
+  });
 })(jQuery);
only in patch2:
unchanged:
--- a/ajax_facets.info
+++ b/ajax_facets.info
@@ -3,6 +3,7 @@ description = Ajax facet filters.
 dependencies[] = facetapi
 dependencies[] = search_api
 dependencies[] = views
+dependencies[] = libraries
 package = Search Toolkit
 core = 7.x
 
only in patch2:
unchanged:
--- a/ajax_facets.install
+++ b/ajax_facets.install
@@ -0,0 +1,33 @@
+<?php
+
+/**
+ * @file
+ * ajax_facets.install file.
+ */
+
+/**
+ * Implements hook_requirements().
+ */
+function ajax_facets_requirements($phase) {
+  $requirements = array();
+  $t = get_t();
+
+  switch ($phase) {
+    case 'runtime':
+      if (!libraries_get_path('history.js')) {
+        $requirements['ajax_facets_error'] = array(
+          'title' => $t('Ajax Facets'),
+          'description' => $t('Please download and unpack "history.js" library to libraries directory.'),
+          'value' => l($t('Download'), 'https://github.com/browserstate/history.js/', array(
+            'attributes' => array(
+              'target' => '_blank',
+            ),
+          )),
+          'severity' => REQUIREMENT_ERROR,
+        );
+      }
+      break;
+  }
+
+  return $requirements;
+}
only in patch2:
unchanged:
--- a/ajax_facets.module
+++ b/ajax_facets.module
@@ -95,6 +95,7 @@ function ajax_facets_add_ajax_js($facet) {
     $included = TRUE;
     $module_path = drupal_get_path('module', 'ajax_facets');
     drupal_add_js($module_path . '/misc/ajax_facets.js');
+    drupal_add_js(libraries_get_path('history.js') . '/scripts/bundled/html4+html5/jquery.history.js', array('group' => JS_LIBRARY));
     drupal_add_css($module_path . '/misc/ajax_facets.css');
     $search_path = $facet->getAdapter()->getSearchPath();
     $filter_key = $facet->getAdapter()->getUrlProcessor()->getFilterKey();