Avoid crash

templates/combined.html

@@ -52,6 +52,7 @@
 {% endblock %}
 
 {% block scripts %}
+{% if subject and lines %}
 <script>
   var copy_subject = document.getElementById("copy-subject");
   var copy_message = document.getElementById("copy-message");
@@ -67,4 +68,5 @@
   });
 
 </script>
+{% endif %}
 {% endblock %}