I have seen the the following statement: in the working draft  that
specifies the XMLHttpRequestObject
"A more complete description of what can be done with
can be found in the IDL
below and its associated details. The IDL is non-normative and
does not intend to conform to [OMGIDL]. Only the language bindings are
It really sounds strange to me. To specify something in IDL that is not
OMG-IDL-conformant but you are going to use the bindings of OMG-IDL.
If you are not going to use the sintax and semantics of OMG-IDL it
could be better not specifying the object in IDL. You could do it
directly in EcmaScript. IDL is accurate when you have to deal with
multiple programming languages, but this is not the case.
Jose Manuel Cantera