The nsIDOMSerializer interface is really a placeholder till the W3C
 DOM Working Group defines a mechanism for serializing DOM nodes.
 An instance of this interface can be used to serialize a DOM document
 or any DOM subtree.
[scriptable, uuid(9fd4ba15-e67c-4c98-b52c-7715f62c9196)]
interface nsIDOMSerializer : nsISupports

Methods

 The subtree rooted by the specified element is serialized to
 a byte stream using the character set specified.
 @param root The root of the subtree to be serialized. This could
             be any node, including a Document.
 @param stream The byte stream to which the subtree is serialized.
 @param charset The name of the character set to use for the encoding
                to a byte stream.  If this string is empty and root is
                a document, the document's character set will be used.
void serializeToStream(in nsIDOMNode root, in nsIOutputStream stream, in AUTF8String charset) 
 The subtree rooted by the specified element is serialized to
 a string.
 
 @param root The root of the subtree to be serialized. This could
             be any node, including a Document.
 @returns The serialized subtree in the form of a Unicode string
AString serializeToString(in nsIDOMNode root)