Few sample scripts for crm 2011
// Getting the Form Type
Xrm.Page.ui.getFormType()
// Set Focus to a field
Xrm.Page.getControl("fieldname").setFocus(true);
// Setting required Field dynamically
Xrm.Page.getAttribute("fieldname").setRequiredLevel("none");
Xrm.Page.getAttribute("fieldname").setRequiredLevel("required");