diff --git a/src/www/js/support.js b/src/www/js/support.js
index e82f4fc9c..9687ea8a1 100644
--- a/src/www/js/support.js
+++ b/src/www/js/support.js
@@ -318,6 +318,7 @@ function overlaps(as,bs) {
 }
 
 function elem(a,as) {
+    if (!as) return false;
     for(var i=0;i<as.length;i++)
 	if(a==as[i]) return true;
     return false;