An attribute specifying, as part of the XML declaration, the version number
of this document. If there is no declaration and if this document supports
the "XML" feature, the value is "1.0". If this document does not support
the "XML" feature, the value is always null.
An attribute specifying, as part of the XML declaration, the version number of this document. If there is no declaration and if this document supports the "XML" feature, the value is "1.0". If this document does not support the "XML" feature, the value is always null.