title: how to get success infomation from server when use model 'save method int Extjs
body: <p>I have knew the success callback in the store' sync process.
  but In my application,I use the model to post  the content to server use the save method.
  and i don't knew how to get the success callback that is same as the sync of the store.
  thank you .</p>
  
  <pre><code>report.data.dm.save({
                                      callback : function() {
                                          Ext.StoreMgr
                                                  .lookup('reportListStore_ID')
                                                  .reload();
                                          Ext.Msg.alert('result', 'report update success');
                                      }
                                  });
  </code></pre>
  
  <p>I use the callback,but I have check that whatever the sever return true or false,the callback will be called.That is'nt What I want to !</p>