Merge pull request #4688 from uclixnjupyternbaccessibility/issue-3961

Closes #3961

notebook/static/tree/js/notebooklist.js

@@ -234,6 +234,7 @@ define([
                     that.select('select-all');
                 }
             });
+
             $('#button-select-all').click(function (e) {
                 // toggle checkbox if the click doesn't come from the checkbox already
                 if (!$(e.target).is('input[type=checkbox]')) {
@@ -811,6 +812,23 @@ define([
         checked = bidi.applyBidi(checked);
         $('#counter-select-all').html(checked===0 ? ' ' : checked);
 
+        //#issue 3961, update the checkbox aria-label when it changed
+        if(selected.length>=1){
+          if($('#select-all').prop("checked")){
+            // $('#button-select-all').attr("aria-label", i18n.msg._("Selected All "+ selected.length +" items"));
+            var msg1 = i18n.msg._("Selected All %d items")
+            $('#button-select-all').attr("aria-label", i18n.msg.sprintf(msg1, selected.length));
+          }
+          else{
+            // $('#button-select-all').attr("aria-label", i18n.msg._("Selected, "+ selected.length+" items"));
+            var msg2 = i18n.msg._("Selected, %d items")
+            $('#button-select-all').attr("aria-label", i18n.msg.sprintf(msg2, selected.length));
+          }
+        }
+        else{
+          $('#button-select-all').attr("aria-label", i18n.msg._("Select All/None"));
+        }
+
         // If at aleast on item is selected, hide the selection instructions.
         if (checked > 0) {
             $('.dynamic-instructions').hide();