Hi,
You have to use the "DataValue" property in order to set the value. Please see: http://msdn2.microsoft.com/en-us/library/aa681847.aspx for more information.
Fx.
Code Snippet crmForm.all.activeon.DataValue = new Date();
crmForm.all.activeon.DataValue = new Date();
Best regards
Casper Jensen
CRM Extensions
www.crmextensions.com