DOMErrorHandler is a callback interface that the DOM
implementation can call when reporting errors that happens while
processing XML data, or when doing some other processing (e.g. validating
a document). A
DOMErrorHandler object can be attached to a
Document using the "error-handler" on the
DOMConfiguration interface. If more than one error needs to
be reported during an operation, the sequence and numbers of the errors
passed to the error handler are implementation dependent.
The application that is using the DOM implementation is expected to
implement this interface.
See also the Document Object Model (DOM) Level 3 Core Specification.