diff --git a/booking.js b/booking.js
index 54cb8b9..034edfc 100644
--- a/booking.js
+++ b/booking.js
@@ -4,7 +4,7 @@
 Drupal.ajax.prototype.commands.bookingAjaxCheckboxes =  function(ajax, response, status) {
     jQuery(function($) {
         var arr = $.parseJSON($('input#booking_email_default_ids').val())
-        $('#booking-manual-email-form').find(':checkbox[name^="' . response.checkboxName .'"]').each(function () {
+        $('#booking-manual-email-form').find(':checkbox[name^="' + response.checkboxName + '"]').each(function () {
             //.prop() doesn't exist in Drupal's old version of jQuery so use .attr() instead
             $(this).attr("checked", ($.inArray($(this).val(), arr) != -1));
         });