ISO IEC 15445:2000 pdf download.Information technology一Document description and processing languages一HyperText Markup Language
2 Conformance
This International Standard distinguishes between conforming documents, validating systems, conforming systems and character set conformance.
2.1 Conforming documents
A document which conforms to this International Standard shall
a. Be a conforming HTML document consisting of a required document type declaration,followed by a single document instance, contained within an [W3C 7.3] document element. The document type declaration may be surrounded by white space consisting of RS, RE, SPACE, TAB and HTML comments. The document instance may also be followed by such white space.
b. Meet the requirements of this International Standard.
2.2 Validating systems
An HTML system is a validating HTML system if
a. It is a validating SGML parser as defined by ISO 8879 subclause 15.4; and
b. It is able to process any conforming HTML document; and
c. It finds and reports an HTML error if one exits; and
d. It does not report an HTML error where none exists.
2.2.1 Documentation of validating systems
Validating systems conforming to this International Standard shall display the following identification text prominently and in the national language of the documentation:
a. In a prominent location in the front matter of publications (normally the title and cover pages),
b. On identifying displays of programs,
c. In promotional and training material.
2.4 Character set conformance
The SGML declaration provided with this International Standard calls for the use of ISO/IEC 10646 Universal Multiple-Octet Coded Character Set (UCS). ISO/IEC 10646 specifies a large number of facilities from which different selections may be made to suit individual applications. As a result it is only practicable to envisage limited conformance to ISO/IEC 10646 as defined in this subclause.
Under limited conformance, the following is required:
a. When the characters described by ISO/IEC 10646 are used, they shall be implemented with the meanings and coded representation specified in ISO/IEC 10646.
b. If a server is unable to express a document using the character set supported by the user agent, it should instead deliver a document in a limited character set and explain the problem to the user agent.
c. Code positions that are either reserved for registration or reserved for future standardization shall not be used.
d. No registered escape sequence shall be used with a meaning other than that defined by ISO/IEC 10646.
The UTF-1 transformation format of ISO/IEC 10646, registered by IANA as ISO-10646-UTF-1, has been removed from ISO/IEC 10646 and should not be used.ISO IEC 15445 pdf download.