Ticket #33349: 33349.2.patch

src/wp-admin/js/post.js

@@ -407 +407 @@
                         return;
                 }
 
-                $.ajax({
-                        type: 'POST',
-                        url: ajaxurl,
-                        async: false,
-                        data: {
-                                action: 'wp-remove-post-lock',
-                                _wpnonce: $('#_wpnonce').val(),
-                                post_ID: $('#post_ID').val(),
-                                active_post_lock: $('#active_post_lock').val()
+                var data = {
+                        action: 'wp-remove-post-lock',
+                        _wpnonce: $('#_wpnonce').val(),
+                        post_ID: $('#post_ID').val(),
+                        active_post_lock: $('#active_post_lock').val()
+                };
+
+                if (window.FormData && window.navigator.sendBeacon) {
+                        var formData = new window.FormData();
+
+                        $.each(data, function(key, value) {
+                                formData.append(key, value);
+                        });
+
+                        if (window.navigator.sendBeacon(ajaxurl, formData)) {
+                                return;
                         }
+                }
+
+                // Fall back to a synchronous POST request.
+                // See https://developer.mozilla.org/en-US/docs/Web/API/Navigator/sendBeacon
+                $.post({
+                        async: false,
+                        data: data,
+                        url: ajaxurl
                 });
         });