Andrew Cunningham wrote:
Lachlan Hunt writes:
Andrew Cunningham wrote:
In theory the docuemnt should only be in one of the unicode
encodings, so without a BOM, the browser should try to render it as
UTF-8.
No, because when it's served as text/html, HTML rules apply, not XML
rules. So without the encoding declared in the HTTP headers or the
meta element, the default of ISO-8859-1 should be used (if served over
HTTP, technically US-ASCII otherwise). However, browsers will
actually interpret ISO-8859-1 as the Windows-1252 superset and will
also attempt to use unspecified heuristics to guess the encoding,
before falling back to the default.
If you're going by the HTTP specs.
Yes, of course, as well as the relevant RFCs for the MIME types.
If you go by the XHTML 1.0 recomendation, appendic C
Appendix C is non-normative.
would indicate that "... that when the XML declaration is not included in a document, the
document can only use the default character encodings UTF-8 or UTF-16.:
That is only true for XML on the condition that the encoding has not
been specified by a higher level protocol. The relevant *normative*
section of the XML rec. states in 4.3.3 Character Encoding in Entities:
In the absence of information provided by an external transport protocol
(e.g. HTTP or MIME), it is a fatal error for an entity including an
encoding declaration to be presented to the XML processor in an encoding
other than that named in the declaration, or for an entity which begins
with neither a Byte Order Mark nor an encoding declaration to use an
encoding other than UTF-8. Note that since ASCII is a subset of UTF-8,
ordinary ASCII entities do not strictly need an encoding declaration.
http://www.w3.org/TR/REC-xml/#charencoding
The point I wnated to make is that there is another way to declare
encoding for docuemnts in UTF-16 or UTF-32: and thats teh BOM; and that
the test should also include BOM detection as an option,
Not according to the HTML 4 Rec, but...
i.e. do various web browsers use the BOM as part of their heuristics.
In reality, yes.
--
Lachlan Hunt
http://lachy.id.au/
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