diff --git a/pinaxcon/templates/symposion/schedule/_grid.html b/pinaxcon/templates/symposion/schedule/_grid.html
index d3c109163592b6ee417bb6aa83534546d86c63e2..7b4847fe3f667f6ea960d9d98d8c7d5c5c340334 100644
--- a/pinaxcon/templates/symposion/schedule/_grid.html
+++ b/pinaxcon/templates/symposion/schedule/_grid.html
@@ -28,7 +28,7 @@
     <tr class="calendar-row">
       <th scope="row" class="time" data-time="{{ timetable.day.date|date:'c' }}T{{ row.time|date:'c' }}"><p>{{ row.time|date:"h:iA" }}</p></th>
       {% for slot in row.slots %}
-      <td class="slot slot-{{ slot.kind.label }}" colspan="{{ slot.colspan }}" rowspan="{{ slot.rowspan }}" data-startdatetime="{{ slot.start_datetime }}" data-enddatetime="{{ slot.end_datetime }}">
+      <td class="slot slot-{{ slot.kind.label }}" colspan="{{ slot.colspan }}" rowspan="{{ slot.rowspan }}" data-starttime="{{ slot.start_datetime|date:'c' }}" data-endtime="{{ slot.end_datetime|date:'c' }}">
         {% with slot.kind.label.lower as label %}
         {% if label == "talk" or label == "tutorial" %}
           {% if slot.content.unpublish and not request.user.is_staff %}