Data object and other controls have some events to help in development process.
Complete list of all events in dataobject or other control with short description can be found in code, but there might be extended events as well. Typically, such events should be attached inside document ready function, to make sure all events are initialized.
Some events like for example
onBeforeSave can be abortable. Also, in some events parameters might be used to change/add data.
onBeforeExport- will fire when dataObject.exportToExcel() function is called. Will pass parameters, which can be changed in the loop. For example, you can change caption, width, format of exported excel sheet.