N/xml Module
Document.doctype
Property Description: The doctype of the XML document. This property is not supported on Internet Explorer.
Type: xml.Element (read-only)
Supported Script Types: All script types For more information, see SuiteScript 2.0 Script Types.
Module: N/xml Module
Since: 2015.2
Search NetSuite - https://system.netsuite.com/app/help/helpcenter.nl?search=Document.doctype

// Code Example 1

//Add additional code

//...

var doctype = xmlDocument.doctype;

//...

//Add additional code



//SOURCE: https://system.netsuite.com/app/help/helpcenter.nl?fid=section_454703308105.html