diff --git a/js/public_selection.js b/js/public_selection.js
index b7045fd..b7c3b3c 100644
--- a/js/public_selection.js
+++ b/js/public_selection.js
@@ -3,6 +3,7 @@
 
   var active = false;
   var selected = {};
+  var downloading = false;
 
   function candidateLinks() {
     return $('#thumbnails a[href], .thumbnails a[href]');
@@ -45,8 +46,6 @@
   }
 
   function itemFromLink($link) {
-    // Prefer semantic list/card wrappers used by Piwigo themes and thumbnail
-    // plugins. gdThumb is only one supported markup, not a dependency.
     var $item = $link.closest('li, .thumbnail, .thumbnailCategory, .gdthumb, .card');
     return $item.length ? $item.first() : $link;
   }
@@ -63,35 +62,43 @@
       var imageId = imageIdFromLink($link);
       var $item = itemFromLink($link);
       $item.addClass('bratonien-selectable').attr('data-bratonien-image-id', imageId);
-      if (selected[imageId]) {
-        $item.addClass('bratonien-selected');
-      }
+      $item.toggleClass('bratonien-selected', !!selected[imageId]);
     });
   }
 
+  function showError(message) {
+    var $error = $('#bratonien-selection-error');
+    if (!message) {
+      $error.prop('hidden', true).text('');
+      return;
+    }
+    $error.text(message).prop('hidden', false);
+  }
+
   function updateBar() {
     var ids = Object.keys(selected);
     $('#bratonien-selection-count').text(ids.length);
-    $('#bratonien-selection-download').prop('disabled', ids.length === 0);
+    $('#bratonien-selection-download').prop('disabled', ids.length === 0 || downloading);
+  }
+
+  function clearSelection() {
+    selected = {};
+    $('.bratonien-selectable').removeClass('bratonien-selected');
+    showError('');
+    updateBar();
   }
 
   function setActive(value) {
     active = value;
     $('body').toggleClass('bratonien-selection-active', active);
     $('#bratonien-selection-bar').prop('hidden', !active);
-    $('#bratonien-selection-toggle').toggleClass('active', active);
+    $('#bratonien-selection-toggle').toggleClass('active', active).attr('aria-pressed', active ? 'true' : 'false');
     refreshSelectableItems();
     if (!active) {
       clearSelection();
     }
   }
 
-  function clearSelection() {
-    selected = {};
-    $('.bratonien-selectable').removeClass('bratonien-selected');
-    updateBar();
-  }
-
   $(document).on('click', '#bratonien-selection-toggle', function (e) {
     e.preventDefault();
     setActive(!active);
@@ -119,6 +126,20 @@
       selected[imageId] = true;
       $item.addClass('bratonien-selected');
     }
+    showError('');
+    updateBar();
+  });
+
+  $(document).on('click', '#bratonien-selection-all', function () {
+    selectableLinks().each(function () {
+      var $link = $(this);
+      var imageId = imageIdFromLink($link);
+      if (imageId) {
+        selected[imageId] = true;
+        itemFromLink($link).addClass('bratonien-selected');
+      }
+    });
+    showError('');
     updateBar();
   });
 
@@ -128,16 +149,53 @@
 
   $(document).on('click', '#bratonien-selection-download', function () {
     var ids = Object.keys(selected);
-    if (!ids.length || !window.BratonienSelectionConfig) {
+    var config = window.BratonienSelectionConfig || {};
+    if (!ids.length || !config.downloadUrl || downloading) {
       return;
     }
 
-    var separator = window.BratonienSelectionConfig.downloadUrl.indexOf('?') === -1 ? '?' : '&';
-    window.location.href = window.BratonienSelectionConfig.downloadUrl + separator + 'bratonien_selection=' + encodeURIComponent(ids.join(','));
+    downloading = true;
+    showError('');
+    $('#bratonien-selection-download').text('Wird vorbereitet …');
+    updateBar();
+
+    $.ajax({
+      url: config.downloadUrl,
+      method: 'POST',
+      dataType: 'json',
+      data: {
+        bratonien_selection_download: 1,
+        image_ids: ids.join(','),
+        pwg_token: config.token || ''
+      }
+    }).done(function (response) {
+      if (!response || !response.ok || !response.download_url) {
+        showError(response && response.error ? response.error : 'Der Download konnte nicht vorbereitet werden.');
+        return;
+      }
+      window.location.href = response.download_url;
+    }).fail(function (xhr) {
+      var message = 'Der Download konnte nicht vorbereitet werden.';
+      if (xhr.responseJSON && xhr.responseJSON.error) {
+        message = xhr.responseJSON.error;
+      }
+      showError(message);
+    }).always(function () {
+      downloading = false;
+      $('#bratonien-selection-download').text('Herunterladen');
+      updateBar();
+    });
+  });
+
+  // The native Batch Downloader button downloads the whole current set and
+  // performs a page round-trip first. When Bratonien selection is available,
+  // the selection mode replaces that control; "Alle auswählen" covers the
+  // complete visible album without the confusing duplicate button.
+  $(function () {
+    $('#batchDownloadLink, #batchDownloadRequest').closest('a').hide();
+    $('#bratonien-selection-toggle').attr('aria-pressed', 'false');
   });
 
-  // Some plugins append thumbnails after the initial page render. Refresh the
-  // markers without depending on any particular thumbnail implementation.
   $(document).ajaxComplete(function () {
     if (active) {
       refreshSelectableItems();