diff --git a/inc/myco_objects.js b/inc/myco_objects.js
index 1d8cfcc..5cdd5bd 100644
--- a/inc/myco_objects.js
+++ b/inc/myco_objects.js
@@ -311,6 +311,9 @@ function Contribution(contributor,cost,title,date,uuid,lastChange) {
   this.contributor=contributor;
   this.cost=cost;
   this.title=title;
+  if (jQuery.type(date)!='date') {
+    date=moment(date).toDate();
+  }
   this.date=date;
   this.uuid=uuid || generate_uuid();
   this.lastChange=lastChange || new Date().getTime();
@@ -320,7 +323,7 @@ function Contribution(contributor,cost,title,date,uuid,lastChange) {
       'uuid': this.uuid,
       'cost': this.cost,
       'title': encodeURIComponent(this.title),
-      'date': this.date,
+      'date': this.date.getTime(),
       'lastChange': this.lastChange,
     };
   }