Custom code can be attached in common way as:

dp.attachEvent(event_name, some_function);

• onRowMark - occurs each time when a row needs to be repaint, blockable.
• onValidatationError - occurs each time when a verificator function catches error, blockable.
• onBeforeUpdate - occurs before data sending to the server, occurs for each row, blockable.
• onBeforeDataSending - occurs after data was validated and it's ready to be sent, occurs once for all rows in sending group, blockable.
• onAfterUpdate - occurs for each action tag in xml response.
• onAfterUpdateFinish - occurs when current data sync operation finished.
• onFullSync - occurs after saving all data ( there are no unsaved changes ).