[fix] [minor] setup serial no editor if serial no field exists
diff --git a/public/js/utils.js b/public/js/utils.js
index c2f2364..61e613b 100644
--- a/public/js/utils.js
+++ b/public/js/utils.js
@@ -38,7 +38,8 @@
 	},
 	
 	setup_serial_no: function(grid_row) {
-		if(grid_row.fields_dict.serial_no.get_status()!=="Write") return;
+		if(!grid_row.fields_dict.serial_no || 
+			grid_row.fields_dict.serial_no.get_status()!=="Write") return;
 		
 		var $btn = $('<button class="btn btn-sm btn-default">Add Serial No</button>')
 			.appendTo($("<div>")