Working With CRM 2011 Fields

To Disable the Lookup fields......

          Xrm.Page.ui.controls.get("fieldnameid").setDisabled(true);

To Retrieve Value from CRM2011 Field........

          Xrm.Page.getAttribute("fieldnameid").getValue();

To make the field mandatory............

 
           Xrm.Page.getAttribute("fieldname").setRequiredLevel("required");

To make non-mandatory........

           Xrm.Page.getAttribute("fieldname").setRequiredLevel("none");

Assign Value to the Picklist........

          Xrm.Page.getAttribute("fieldname").setValue(1);

To Make the Field Empty(null).......

           Xrm.Page.getAttribute("fieldname").setValue(null); 


Happy CRMing................