diff --git a/term_reference_tree/term_reference_tree.js b/term_reference_tree/term_reference_tree.js
index 1a4daab..333a65c 100644
--- a/www/sites/all/modules/contrib/term_reference_tree/term_reference_tree.js
+++ b/www/sites/all/modules/contrib/term_reference_tree/term_reference_tree.js
@@ -265,9 +265,9 @@ function checkMaxChoices(item, checkbox) {
       var input_type =
           ( item.has('input[type=checkbox]').size() > 0 ) ? 'checkbox' : 'radio';
 
-      if(checkbox.attr('checked')) {
-        checkbox.parents('ul.term-reference-tree-level li').children('div.form-item').children('input[type=checkbox]').each(function() {
-          $(this).attr('checked', checkbox.attr('checked'));
+      if(checkbox.prop('checked')) {
+        checkbox.parents('ul.term-reference-tree-level li').children('div.form-item').find('input[type=checkbox]').each(function() {
+          $(this).prop('checked', checkbox.prop('checked'));
 
           if(track_list_container) {
             label_element = $(this).next();