Save new record in Web Resource and get its Id

Hello,

When I click New button and create a new record, opens a new form(Client), In that form I have web resource (type=HTML), in this web resource I need to save this record and get Id.

How can i do this ? I try to write 

window.parent.Xrm.Page.data.save();
window.parent.Xrm.Page.data.refresh();

var entityId = window.parent.Xrm.Page.data.entity.getId();

but var entityId = ""

How can I get Id ? 

Thanks.