diff --git a/CHANGELOG.txt b/CHANGELOG.txt
index fa3dd35e78eb0cfa308e35c3b0821756216d589b..d311993f85db33dbfc09a53463c91273b3a374d2 100644
--- a/CHANGELOG.txt
+++ b/CHANGELOG.txt
@@ -8,6 +8,9 @@ Drupal 7.51, xxxx-xx-xx (development version)
 - Log messages are now XSS filtered on display.
 - Draggable tables do now work on touch screen devices.
 - Added setting for allowing double underscores in CSS identifiers.
+- If a user navigates away from a page while an AJAX request is running they
+  will no longer get an error message saying "An AJAX HTTP request terminated
+  abnormally"
 - Numerous performance improvements.
 - Numerous small bugfixes.
 - Numerous API documentation improvements.
diff --git a/misc/ajax.js b/misc/ajax.js
index bb4a6e14f9962a48bb0a2670638d840751fc0fe2..c944ebbf246193da3c9fc209e58b72d240f61ff9 100644
--- a/misc/ajax.js
+++ b/misc/ajax.js
@@ -476,7 +476,7 @@ Drupal.ajax.prototype.getEffect = function (response) {
  * Handler for the form redirection error.
  */
 Drupal.ajax.prototype.error = function (xmlhttprequest, uri, customMessage) {
-  alert(Drupal.ajaxError(xmlhttprequest, uri, customMessage));
+  Drupal.displayAjaxError(Drupal.ajaxError(xmlhttprequest, uri, customMessage));
   // Remove the progress element.
   if (this.progress.element) {
     $(this.progress.element).remove();
diff --git a/misc/autocomplete.js b/misc/autocomplete.js
index d71441b6c73df1a0b538278a9f4a2c57f4a27765..af090713c730f095881c7040947cc064232296e4 100644
--- a/misc/autocomplete.js
+++ b/misc/autocomplete.js
@@ -310,7 +310,7 @@ Drupal.ACDB.prototype.search = function (searchString) {
         }
       },
       error: function (xmlhttp) {
-        alert(Drupal.ajaxError(xmlhttp, db.uri));
+        Drupal.displayAjaxError(Drupal.ajaxError(xmlhttp, db.uri));
       }
     });
   }, this.delay);
diff --git a/misc/drupal.js b/misc/drupal.js
index 427c4a1e29ea648788083c219678712ed76226dc..03eef50edc943201278ef1c086055714297b02cd 100644
--- a/misc/drupal.js
+++ b/misc/drupal.js
@@ -413,6 +413,29 @@ Drupal.getSelection = function (element) {
   return { 'start': element.selectionStart, 'end': element.selectionEnd };
 };
 
+/**
+ * Add a global variable which determines if the window is being unloaded.
+ *
+ * This is primarily used by Drupal.displayAjaxError().
+ */
+Drupal.beforeUnloadCalled = false;
+$(window).bind('beforeunload pagehide', function () {
+    Drupal.beforeUnloadCalled = true;
+});
+
+/**
+ * Displays a JavaScript error from an Ajax response when appropriate to do so.
+ */
+Drupal.displayAjaxError = function (message) {
+  // Skip displaying the message if the user deliberately aborted (for example,
+  // by reloading the page or navigating to a different page) while the Ajax
+  // request was still ongoing. See, for example, the discussion at
+  // http://stackoverflow.com/questions/699941/handle-ajax-error-when-a-user-clicks-refresh.
+  if (!Drupal.beforeUnloadCalled) {
+    alert(message);
+  }
+};
+
 /**
  * Build an error message from an Ajax response.
  */