How to retrive Json error response

Hi,

I have a store with records. I ll do CRUD operations using service calls. During create / update / delete i am using

Code:

store.sync(
            {
                success: function()
                {
                    Ext.Msg.alert('Status', 'Successfully saved');
                },
                failure: function()
                {
                    Ext.Msg.alert('Attention', 'Failed to save');
                },
                callback: function()
                {
                   store.load();
                },
                scope: this
            })

If there is a database exception it will be thrown through services.

My question is how can i retrieve exception message from Json response.

Please help me.

Thanks and regards

Rakesh