How to assign/ set a record to subgrid in MS CRM 2011 online using javascript

Hi,

I am using MS CRM 2011 online.

In this i want to assign / set / insert a record value in to subgrid using java script.

Example: I have retrieved a lookup value from a field and i want to set / insert this value into subgrid.

can anyone help us to solve this requirement.

Thanks in Advance

Chandra