getDataXml (Client API reference)
Returns a string representing the XML that will be sent to the server when the record is saved. Only data in columns that have changed or have their submit mode set to "always" are sent to the server.
Syntax
formContext.data.entity.getDataXml();
Return Value
Type: String.
Description: In this example, the following three columns for an account record were updated: name, accountnumber, telephone2.
"<account><name>Contoso</name><accountnumber>55555</accountnumber><telephone2>425 555-1234</telephone2></account>"
Remarks
This method does not work with Microsoft Dynamics 365 for tablets.