Getting grid in form editing events in jqgrid

Question

I am trying to add some user data in postdata in editing a form using jqgrid. The grid id is somehow related to the data I want to add. However, the grid id is randomly generated, so I can't hard code it. So my idea is to extract the id from event callbacks and add postdata. From reading the api, I think the event onclickSubmitshould be a way. However, I could not figure out how to get the grid / grid id from the parameter. Can someone enlighten me about this?

Here is a link to jqrid form editing events. http://www.trirand.com/jqgridwiki/doku.php?id=wiki:form_editing