diff --git a/src/js/host/host.js b/src/js/host/host.js
index 3ab1414..0bcfd04 100644
--- a/src/js/host/host.js
+++ b/src/js/host/host.js
@@ -1726,7 +1726,7 @@ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 	{
 		var data		= evt && evt.data,
 			msg_win		= evt && evt.source,
-			params		= data && (data.indexOf(GUID) != -1) && ParamHash(data),
+			params		= data && typeof data == STR && (data.indexOf(GUID) != -1) && ParamHash(data),
 			tgtID 		= params && params.id,
 			ifr			= tgtID && _elt(tgtID),
 			fr_win		= ifr && _ifr_view(ifr),