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--------------------------------------------------------------------------------
2 HTML Working Group T. Berners-Lee
3 INTERNET-DRAFT MIT/W3C
4 D. Connolly
5 Expires: In six months June 16, 1995
7 Hypertext Markup Language - 2.0
9 Status of this Memo
11 This document is an Internet-Draft. Internet-Drafts are working
12 documents of the Internet Engineering Task Force (IETF), its areas, and
13 its working groups. Note that other groups may also distribute working
14 documents as Internet-Drafts.
16 Internet-Drafts are draft documents valid for a maximum of six months
17 and may be updated, replaced, or obsoleted by other documents at any
18 time. It is inappropriate to use Internet-Drafts as reference material
19 or to cite them other than as ``work in progress.''
21 To learn the current status of any Internet-Draft, please check the
22 1id-abstracts.txt listing contained in the Internet-Drafts Shadow
23 Directories on ftp.is.co.za (Africa), nic.nordu.net (Europe),
24 munnari.oz.au (Pacific Rim), ds.internic.net (US East Coast), or
25 ftp.isi.edu (US West Coast).
27 Distribution of this document is unlimited. Please send comments to the
28 HTML working group (HTML-WG) of the Internet Engineering Task Force
29 (IETF) at . Discussions of the group are archived at
30 .
32 ABSTRACT
34 The Hypertext Markup Language (HTML) is a simple markup language
35 used to create hypertext documents that are platform
36 independent. HTML documents are SGML documents with generic
37 semantics that are appropriate for representing information from
38 a wide range of domains. HTML markup can represent hypertext
39 news, mail, documentation, and hypermedia; menus of options;
40 database query results; simple structured documents with
41 in-lined graphics; and hypertext views of existing bodies of
42 information.
44 HTML has been in use by the World Wide Web (WWW) global
45 information initiative since 1990. This specification roughly
46 corresponds to the capabilities of HTML in common use prior to
47 June 1994. HTML is an application of ISO Standard 8879:1986
48 Information Processing Text and Office Systems; Standard
49 Generalized Markup Language (SGML).
51 The `text/html' Internet Media Type (RFC 1590) and MIME Content
52 Type (RFC 1521) is defined by this specification.
54 CONTENTS
56 1 Introduction .......................................... 3
57 1.1 Scope ................................................. 3
58 1.2 Conformance ........................................... 3
59 2 Terms ................................................. 5
60 3 HTML as an Application of SGML ........................ 9
61 3.1 SGML Documents ........................................ 9
62 3.2 HTML Lexical Syntax .................................. 11
63 3.3 HTML Public Text Identifiers ......................... 15
64 3.4 Example HTML Document ................................ 16
65 4 HTML as an Internet Media Type ....................... 16
66 4.1 text/html media type ................................. 16
67 4.2 HTML Document Representation ......................... 17
68 5 Document Structure ................................... 18
69 5.1 Document Element: HTML ............................... 19
70 5.2 Head: HEAD ........................................... 19
71 5.3 Body: BODY ........................................... 22
72 5.4 Headings: H1 ... H6 .................................. 22
73 5.5 Block Structuring Elements ........................... 23
74 5.6 List Elements ........................................ 25
75 5.7 Phrase Markup ........................................ 28
76 5.8 Line Break: BR ....................................... 31
77 5.9 Horizontal Rule: HR .................................. 31
78 5.10 Image: IMG ........................................... 31
79 6 Characters, Words, and Paragraphs .................... 33
80 6.1 The HTML Document Character Set ...................... 33
81 7 Hyperlinks ........................................... 34
82 7.1 Accessing Resources .................................. 34
83 7.2 Activation of Hyperlinks ............................. 34
84 7.3 Simultaneous Presentation of Image Resources ......... 35
85 7.4 Fragment Identifiers ................................. 35
86 7.5 Queries and Indexes .................................. 35
87 7.6 Image Maps ........................................... 36
88 8 Forms ................................................ 36
89 8.1 Form Elements ........................................ 37
90 8.2 Form Submission ...................................... 42
91 9 HTML Public Text ..................................... 45
92 9.1 HTML DTD ............................................. 45
93 9.2 Strict HTML DTD ...................................... 56
94 9.3 Level 1 HTML DTD ..................................... 57
95 9.4 Strict Level 1 HTML DTD .............................. 58
96 9.5 SGML Declaration for HTML ............................ 58
97 9.6 Sample SGML Open Entity Catalog for HTML ............. 60
98 9.7 Character Entity Sets ................................ 61
99 10 Security Considerations .............................. 63
100 11 References ........................................... 64
101 12 Acknowledgments ...................................... 65
102 12.1 Authors' Addresses ................................... 66
103 13 The HTML Coded Character Set ......................... 66
104 14 Proposed Entities .................................... 69
106 1. Introduction
108 The HyperText Markup Language (HTML) is a simple data format
109 used to create hypertext documents that are portable from one
110 platform to another. HTML documents are SGML documents with
111 generic semantics that are appropriate for representing
112 information from a wide range of domains.
114 As HTML is an application of SGML, this specification assumes a
115 working knowledge of [SGML].
117 1.1. Scope
119 HTML has been in use by the World-Wide Web (WWW) global
120 information initiative since 1990. This specification
121 corresponds to the capabilities of HTML in common use prior to
122 June 1994 and referred to as ``HTML 2.0''.
124 HTML is an application of ISO Standard 8879:1986 _Information
125 Processing Text and Office Systems; Standard Generalized Markup
126 Language_ (SGML). The HTML Document Type Definition (DTD) is a
127 formal definition of the HTML syntax in terms of SGML.
129 This specification also defines HTML as an Internet Media
130 Type[IMEDIA] and MIME Content Type[MIME] called `text/html'. As
131 such, it defines the semantics of the HTML syntax and how that
132 syntax should be interpreted by user agents.
134 1.2. Conformance
136 This specification governs the syntax of HTML documents and
137 aspects of the behavior of HTML user agents.
139 1.2.1. Documents
141 A document is a conforming HTML document if:
143 * It is a conforming SGML document, and it conforms to the
144 HTML DTD (see 9.1, "HTML DTD").
146 NOTE - There are a number of syntactic idioms that
147 are not supported or are supported inconsistently in
148 some historical user agent implementations. These
149 idioms are identified in notes like this throughout
150 this specification.
152 * It conforms to the application conventions in this
153 specification. For example, the value of the HREF attribute
154 of the element must conform to the URI syntax.
156 * Its document character set includes [ISO-8859-1] and
157 agrees with [ISO-10646]; that is, each code position listed
158 in 13, "The HTML Coded Character Set" is included, and each
159 code position in the document character set is mapped to the
160 same character as [ISO-10646] designates for that code
161 position.
163 NOTE - The document character set is somewhat
164 independent of the character encoding scheme used to
165 represent a document. For example, the `ISO-2022-JP'
166 character encoding scheme can be used for HTML
167 documents, since its repertoire is a subset of the
168 [ISO-10646] repertoire. The critical distinction is
169 that numeric character references agree with
170 [ISO-10646] regardless of how the document is
171 encoded.
173 1.2.2. Feature Test Entities
175 The HTML DTD defines a standard HTML document type and several
176 variations, by way of feature test entities. Feature test
177 entities are declarations in the HTML DTD that control the
178 inclusion or exclusion of portions of the DTD.
180 HTML.Recommended
181 Certain features of the language are necessary for
182 compatibility with widespread usage, but they may
183 compromise the structural integrity of a document. This
184 feature test entity selects a more prescriptive document
185 type definition that eliminates those features. It is
186 set to `IGNORE' by default.
188 For example, in order to preserve the structure of a
189 document, an editing user agent may translate HTML
190 documents to the recommended subset, or it may require
191 that the documents be in the recommended subset for
192 import.
194 HTML.Deprecated
195 Certain features of the language are necessary for
196 compatibility with earlier versions of the
197 specification, but they tend to be used and implemented
198 inconsistently, and their use is deprecated. This
199 feature test entity enables a document type definition
200 that allows these features. It is set to `INCLUDE' by
201 default.
203 Documents generated by translation software or editing
204 software should not contain deprecated idioms.
206 1.2.3. User Agents
208 An HTML user agent conforms to this specification if:
210 * It parses the characters of an HTML document into data
211 characters and markup according to [SGML].
213 NOTE - In the interest of robustness and
214 extensibility, there are a number of widely deployed
215 conventions for handling non-conforming documents.
216 See 4.2.1, "Undeclared Markup Error Handling" for
217 details.
219 * It supports the `ISO-8859-1' character encoding scheme and
220 processes each character in the ISO Latin Alphabet No. 1 as
221 specified in 6.1, "The HTML Document Character Set".
223 NOTE - To support non-western writing systems, HTML
224 user agents are encouraged to support
225 `ISO-10646-UCS-2' or similar character encoding
226 schemes and as much of the character repertoire of
227 [ISO-10646] as is practical.
229 * It behaves identically for documents whose parsed token
230 sequences are identical.
232 For example, comments and the whitespace in tags disappear
233 during tokenization, and hence they do not influence the
234 behavior of conforming user agents.
236 * It allows the user to traverse (or at least attempt to
237 traverse, resources permitting) all hyperlinks from
238 elements in an HTML document.
240 An HTML user agent is a level 2 user agent if, additionally:
242 * It allows the user to express all form field values
243 specified in an HTML document and to (attempt to) submit the
244 values as requests to information services.
246 2. Terms
248 absolute URI
249 a URI in absolute form, as per [URL]
251 anchor
252 one of two ends of a hyperlink; typically, a phrase
253 marked as an element.
255 base URI
256 URI used as the base of an HTML document for the purpose
257 of resolving hyperlink destinations.
259 character
260 An atom of information, for example a letter or a digit.
261 Graphic characters have associated glyphs, where as
262 control characters have associated processing semantics.
264 character encoding
265 scheme
266 A function whose domain is the set of sequences of
267 octets, and whose range is the set of sequences of
268 characters from a character repertoire; that is, a
269 sequence of octets and a character encoding scheme
270 determines a sequence of characters.
272 character repertoire
273 A finite set of characters; e.g. the range of a coded
274 character set.
276 code position
277 An integer. A coded character set and a code position
278 from its domain determine a character.
280 coded character set
281 A function whose domain is a subset of the integers and
282 whose range is a character repertoire. That is, for some
283 set of integers (usually of the form {0, 1, 2, ..., N}
284 ), a coded character set and an integer in that set
285 determine a character. Conversely, a character and a
286 coded character set determine the character's code
287 position (or, in rare cases, a few code positions).
289 conforming HTML user
290 agent
291 A user agent that conforms to this specification in its
292 processing of the Internet Media Type `text/html'.
294 data character
295 Characters other than markup, which make up the content
296 of elements.
298 document character set
299 a coded character set whose range includes all
300 characters used in a document. Every SGML document has
301 exactly one document character set. Numeric character
302 references are resolved via the document character set.
304 DTD
305 document type definition. Rules that apply SGML to the
306 markup of documents of a particular type, including a
307 set of element and entity declarations. [SGML]
309 element
310 A component of the hierarchical structure defined by a
311 document type definition; it is identified in a document
312 instance by descriptive markup, usually a start-tag and
313 end-tag. [SGML]
315 end-tag
316 Descriptive markup that identifies the end of an
317 element. [SGML]
319 entity
320 data with an associated notation or interpretation; for
321 example, a sequence of octets associated with an
322 Internet Media Type. [SGML]
324 fragment identifier
325 the portion of an HREF attribute value following the `#'
326 character which modifies the presentation of the
327 destination of a hyperlink.
329 form data set
330 a sequence of name/value pairs; the names are given by
331 an HTML document and the values are given by a user.
333 HTML document
334 An SGML document conforming to this document type
335 definition.
337 hyperlink
338 a relationship between two anchors, called the tail and
339 the head.
341 markup
342 Syntactically delimited characters added to the data of
343 a document to represent its structure. There are four
344 different kinds of markup: descriptive markup (tags),
345 references, markup declarations, and processing
346 instructions. [SGML]
348 may
349 A document or user interface is conforming whether this
350 statement applies or not.
352 media type
353 an Internet Media Type, as per [IMEDIA].
355 message entity
356 a head and body. The head is a collection of name/value
357 fields, and the body is a sequence of octets. The head
358 defines the content type and content transfer encoding
359 of the body. [MIME]
361 minimally conforming
362 HTML user agent
363 A user agent that conforms to this specification except
364 for form processing. It may only process level 1 HTML
365 documents.
367 must
368 Documents or user agents in conflict with this statement
369 are not conforming.
371 numeric character
372 reference
373 markup that refers to a character by its code position
374 in the document character set.
376 SGML document
377 A sequence of characters organized physically as a set
378 of entities and logically into a hierarchy of elements.
379 An SGML document consists of data characters and markup;
380 the markup describes the structure of the information
381 and an instance of that structure. [SGML]
383 shall
384 If a document or user agent conflicts with this
385 statement, it does not conform to this specification.
387 should
388 If a document or user agent conflicts with this
389 statement, undesirable results may occur in practice
390 even though it conforms to this specification.
392 start-tag
393 Descriptive markup that identifies the start of an
394 element and specifies its generic identifier and
395 attributes. [SGML]
397 syntax-reference
398 character set
399 A coded character set whose range includes all
400 characters used for markup; e.g. name characters and
401 delimiter characters.
403 tag
404 Markup that delimits an element. A tag includes a name
405 which refers to an element declaration in the DTD, and
406 may include attributes. [SGML]
408 text entity
409 A finite sequence of characters. A text entity typically
410 takes the form of a sequence of octets with some
411 associated character encoding scheme, transmitted over
412 the network or stored in a file. [SGML]
414 typical
415 Typical processing is described for many elements. This
416 is not a mandatory part of the specification but is
417 given as guidance for designers and to help explain the
418 uses for which the elements were intended.
420 URI
421 A Universal Resource Identifier is a formatted string
422 that serves as an identifier for a resource, typically
423 on the Internet. URIs are used in HTML to identify the
424 destination of hyperlinks. URIs in common practice
425 include Uniform Resource Locators (URLs)[URL] and
426 Relative URLs [RELURL].
428 user agent
429 A component of a distributed system that presents an
430 interface and processes requests on behalf of a user;
431 for example, a www browser or a mail user agent.
433 WWW
434 The World-Wide Web is a hypertext-based, distributed
435 information system created by researchers at CERN in
436 Switzerland. Parsing Example
484 Some text. *wow*
486 An HTML user agent should use the SGML declaration that is given
487 in 9.5, "SGML Declaration for HTML". According to its document
488 character set, `*' refers to an asterisk character, `*'.
490 The instance above is regarded as the following sequence of
491 terminals:
493 1. start-tag: TITLE
495 2. data characters: ``Parsing Example''
497 3. end-tag: TITLE
499 4. start-tag: P
501 5. data characters ``Some text. ''
503 6. start-tag: EM
505 7. data characters: ``*wow*''
507 8. end-tag: EM
509 9. end-tag: P
511 The start symbol of the DTD grammar is HTML, and the productions
512 are given in the public text identified by `-//IETF//DTD HTML
513 2.0//EN' (9.1, "HTML DTD"). The terminals above parse as:
515 HTML
516 |
517 \-HEAD
518 | |
519 | \-TITLE
520 | |
521 | \-
522 | |
523 | \-"Parsing Example"
524 | |
525 | \-
526 |
527 \-BODY
528 |
529 \-P
530 |
531 \-
532 |
533 \-"Some text. "
534 |
535 \-EM
536 | |
537 | \-
538 | |
539 | \-"*wow*"
540 | |
541 | \-
542 |
543 \-
545 Some of the elements are delimited explicity by tags, while the
546 boundaries of others are inferred. The element contains a
547 element and a element. The contains
548 , which is explicitly delimited by start- and end-tags.
550 3.2. HTML Lexical Syntax
552 SGML specifies an abstract syntax and a reference concrete
553 syntax. Aside from certain quantities and capacities (e.g. the
554 limit on the length of a name), all HTML documents use the
555 reference concrete syntax. In particular, all markup characters
556 are in the repertoire of [ISO-646]. Data characters are drawn
557 from the document character set (see 6, "Characters, Words, and
558 Paragraphs").
560 A complete discussion of SGML parsing, e.g. the mapping of a
561 sequence of characters to a sequence of tags and data, is left
562 to the SGML standard[SGML]. This section is only a summary.
564 3.2.1. Data Characters
566 Any sequence of characters that do not constitute markup (see
567 9.6 ``Delimiter Recognition'' of [SGML]) are mapped directly to
568 strings of data characters. Some markup also maps to data
569 character strings. Numeric character references map to
570 single-character strings, via the document character set. Each
571 reference to one of the general entities defined in the HTML DTD
572 maps to a single-character string.
574 For example,
576 abc<def => "abc","<","def"
577 abc<def => "abc","<","def"
579 The terminating semicolon on entity or numeric character
580 references is only necessary when the character following the
581 reference would otherwise be recognized as part of the name (see
582 9.4.5 ``Reference End'' in [SGML]).
584 abc < def => "abc ","<"," def"
585 abc < def => "abc ","<"," def"
587 An ampersand is only recognized as markup when it is followed by
588 a letter or a `#' and a digit:
590 abc & lt def => "abc & lt def"
591 abc &# 60 def => "abc &# 60 def"
593 A useful technique for translating plain text to HTML is to
594 replace each '<', '&', and '>' by an entity reference or numeric
595 character reference as follows:
597 ENTITY NUMERIC
598 CHARACTER REFERENCE CHAR REF CHARACTER DESCRIPTION
599 --------- ---------- ----------- ---------------------
600 & & & Ampersand
601 < < < Less than
602 > > > Greater than
604 NOTE - There are SGML mechanisms, CDATA and RCDATA
605 declared content, that allow most `<', `>', and `&'
606 characters to be entered without the use of entity
607 references. Because these mechanisms tend to be used and
608 implemented inconsistently, and because they conflict
609 with techniques for reducing HTML to 7 bit ASCII for
610 transport, they are deprecated in this version of HTML.
611 See 5.5.2.1, "Example and Listing: XMP, LISTING".
613 3.2.2. Tags
615 Tags delimit elements such as headings, paragraphs, lists,
616 character highlighting, and links. Most HTML elements are
617 identified in a document as a start-tag, which gives the element
618 name and attributes, followed by the content, followed by the
619 end tag. Start-tags are delimited by `<' and `>'; end tags are
620 delimited by `</' and `>'. An example is:
622 <H1>This is a Heading</H1>
624 Some elements only have a start-tag without an end-tag. For
625 example, to create a line break, you use the `<BR>' tag.
626 Additionally, the end tags of some other elements, such as
627 Paragraph (`</P>'), List Item (`</LI>'), Definition Term
628 (`</DT>'), and Definition Description (`<DD>') elements, may be
629 omitted.
631 The content of an element is a sequence of data character
632 strings and nested elements. Some elements, such as anchors,
633 cannot be nested. Anchors and character highlighting may be put
634 inside other constructs. See the HTML DTD, 9.1, "HTML DTD" for
635 full details.
637 NOTE - The SGML declaration for HTML specifies SHORTTAG
638 YES, which means that there are other valid syntaxes for
639 tags, such as NET tags, `<EM/.../'; empty start tags,
640 `<>'; and empty end-tags, `</>'. Until support for these
641 idioms is widely deployed, their use is strongly
642 discouraged.
644 3.2.3. Names
646 A name consists of a letter followed by letters, digits,
647 periods, or hyphens. The length of a name is limited to 72
648 characters by the `NAMELEN' parameter in the SGML delcaration
649 for HTML, 9.5, "SGML Declaration for HTML". Element and
650 attribute names are not case sensitive, but entity names are.
651 For example, `<BLOCKQUOTE>', `<BlockQuote>', and `<blockquote>'
652 are equivalent, whereas `&' is different from `&'.
654 In a start-tag, the element name must immediately follow the tag
655 open delimiter `<'.
657 3.2.4. Attributes
659 In a start-tag, white space and attributes are allowed between
660 the element name and the closing delimiter. An attribute
661 specification typically consists of an attribute name, an equal
662 sign, and a value, though some attribute specifications may be
663 just a name token. White space is allowed around the equal sign.
665 The value of the attribute may be either:
667 * A string literal, delimited by single quotes or double
668 quotes and not containing any occurrences of the delimiting
669 character.
671 NOTE - Some historical implementations consider any
672 occurrence of the `>' character to signal the end of
673 a tag. For compatibility with such implementations,
674 when `>' appears in an attribute value, it should be
675 represented with a numeric character reference. For
676 example, `<IMG SRC="eq1.jpg" alt="a>b">' should be
677 written `<IMG SRC="eq1.jpg" alt="a>b">' or `<IMG
678 SRC="eq1.jpg" alt="a>b">'.
680 * A name token (a sequence of letters, digits, periods, or
681 hyphens). Name tokens are not case sensitive.
683 NOTE - Some historical implementations allow any
684 character except space or `>' in a name token.
686 In this example, <img> is the element name, src is the attribute
687 name, and `http://host/dir/file.gif' is the attribute value:
689 <img src='http://host/dir/file.gif'>
691 A useful technique for computing an attribute value literal for
692 a given string is to replace each quote and white space
693 character by an entity reference or numeric character reference
694 as follows:
696 ENTITY NUMERIC
697 CHARACTER REFERENCE CHAR REF CHARACTER DESCRIPTION
698 --------- ---------- ----------- ---------------------
699 HT Tab
700 LF
Line Feed
701 CR
Carriage Return
702 SP Space
703 " " " Quotation mark
704 & & & Ampersand
706 For example:
708 <IMG SRC="image.jpg" alt="First "real" example">
710 The `NAMELEN' parameter in the SGML declaration (9.5, "SGML
711 Declaration for HTML") limits the length of an attribute value
712 to 1024 characters.
714 Attributes such as ISMAP and COMPACT may be written using a
715 minimized syntax (see 7.9.1.2 ``Omitted Attribute Name'' in
716 [SGML]). The markup:
718 <UL COMPACT="compact">
720 can be written using a minimized syntax:
722 <UL COMPACT>
724 NOTE - Some historical implementations only understand
725 the minimized syntax.
727 3.2.5. Comments
729 To include comments in an HTML document, use a comment
730 declaration. A comment declaration consists of `<!' followed by
731 zero or more comments followed by `>'. Each comment starts with
732 `--' and includes all text up to and including the next
733 occurrence of `--'. In a comment declaration, white space is
734 allowed after each comment, but not before the first comment.
735 The entire comment declaration is ignored.
737 NOTE - Some historical HTML implementations incorrectly
738 consider any `>' character to be the termination of a
739 comment.
741 For example:
743 <!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
744 <HEAD>
745 <TITLE>HTML Comment Example
746
747
748
749
750
751
753 3.3. HTML Public Text Identifiers
755 To identify information as an HTML document conforming to this
756 specification, each document should start with one of the
757 following document type declarations.
759
761 This document type declaration refers to the HTML DTD in 9.1,
762 "HTML DTD".
764 NOTE - If the body of a `text/html' message entity does
765 not begin with a document type declaration, an HTML user
766 agent should infer the above document type declaration.
768
770 This document type declaration also refers to the HTML DTD which
771 appears in 9.1, "HTML DTD".
773
775 This document type declaration refers to the level 1 HTML DTD in
776 9.3, "Level 1 HTML DTD". Form elements must not occur in level 1
777 documents.
779
780
782 These two document type declarations refer to the HTML DTD in
783 9.2, "Strict HTML DTD" and 9.4, "Strict Level 1 HTML DTD". They
784 refer to the more structurally rigid definition of HTML.
786 HTML user agents may support other document types. In
787 particular, they may support other formal public identifiers, or
788 other document types altogether. They may support an internal
789 declaration subset with supplemental entity, element, and other
790 markup declarations.
792 3.4. Example HTML Document
794
795
796
797
798 Structural Example
799
800 First Header
801 This is a paragraph in the example HTML file. Keep in mind
802 that the title does not appear in the document text, but that
803 the header (defined by H1) does.
804
805 - First item in an ordered list.
806
- Second item in an ordered list.
807
808 - Note that lists can be nested;
809
- Whitespace may be used to assist in reading the
810 HTML source.
811
812 - Third item in an ordered list.
813
814 This is an additional paragraph. Technically, end tags are
815 not required for paragraphs, although they are allowed. You can
816 include character highlighting in a paragraph. This sentence
817 of the paragraph is emphasized. Note that the </P>
818 end tag has been omitted.
819
820 
821 Be sure to read these bold instructions.
822
824 4. HTML as an Internet Media Type
826 An HTML user agent allows users to interact with resources which
827 have HTML representations. At a minimum, it must allow users to
828 examine and navigate the content of HTML level 1 documents. HTML
829 user agents should be able to preserve all formatting
830 distinctions represented in an HTML document, and be able to
831 simultaneously present resources referred to by IMG elements
832 (they may ignore some formatting distinctions or IMG resources
833 at the request of the user). Level 2 HTML user agents should
834 support form entry and submission.
836 4.1. text/html media type
838 This specification defines the Internet Media Type[IMEDIA]
839 (formerly referred to as the Content Type[MIME]) called
840 `text/html'. The following is to be registered with [IANA].
842 Media Type name
843 text
845 Media subtype name
846 html
848 Required parameters
849 none
851 Optional parameters
852 level, charset
854 Encoding considerations
855 any encoding is allowed
857 Security considerations
858 see 10, "Security Considerations"
860 The optional parameters are defined as follows:
862 Level
863 The level parameter specifies the feature set used in
864 the document. The level is an integer number, implying
865 that any features of same or lower level may be present
866 in the document. Level 1 is all features defined in this
867 specification except those that require the
2242 The initial state of the form data set is:
2244 name
2245 ``''
2247 gender
2248 ``male''
2250 family
2251 ``''
2253 other
2254 ``''
2256 nickname
2257 ``''
2259 Note that the radio input has an initial value, while the
2260 checkbox has none.
2262 The user might edit the fields and request that the form be
2263 submitted. At that point, suppose the values are:
2265 name
2266 ``John Doe''
2268 gender
2269 ``male''
2271 family
2272 ``5''
2274 city
2275 ``kent,miami''
2277 other
2278 ``abc\ndef''
2280 nickname
2281 ``J&D''
2283 The user agent then conducts an HTTP POST transaction using the
2284 URI `http://www.w3.org/sample'. The message body would be
2285 (ignore the line break):
2287 name=John+Doe&gender=male&family=5&city=kent%2Cmiami&
2288 other=abc%0D%0Adef&nickname=J%26D
2290 9. HTML Public Text
2292 9.1. HTML DTD
2294 This is the Document Type Definition for the HyperText Markup
2295 Language, level 2.
2297
2309
2315
2316 ...
2317
2318 --
2319 >
2321
2323
2333
2335 ]]>
2337
2346
2352
2358
2360
2365
2369
2382
2383
2385
2387
2389
2391 %ISOlat1;
2393
2394
2395
2396
2398
2400
2416
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2420
2422
2424
2427
2429
2433
2434
2436
2437
2440
2443
2447
2448
2449
2451
2452
2453
2454
2455
2456
2457
2459
2461 ]]>
2463
2465
2466
2470
2472
2474
2476
2484 Heading
2487 is preferred to
2488 Heading
2489 -->
2490 ]]>
2492
2494
2495 "
2500 >
2501
2502
2503
2504
2505
2506
2507
2508
2510
2512
2513 #AttVal(Alt)"
2519 >
2521
2522
2523
2524
2525
2527
2529
2530
2534
2536
2537
2538
2542
2544
2545
2548
2551
2554
2557
2560
2564
2565
2566
2567
2568
2569
2571
2573
2575 ]]>
2577
2579
2581 ]]>
2583
2585
2589
2590
2591
2592
2597
2598
2600
2608
2609
2613
2618
2619
2621
2622
2624
2627 ]]>
2629
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2639
2643
2644
2648
2649
2650
2651
2653
2654
2658
2662
2663
2664
2665
2667
2668 Directory"
2672 >
2673 Menu"
2677 >
2679
2680
2681
2682
2684
2685
2689
2691
2693 Heading
2696 Text ...
2697 is preferred to
2698
Heading
2699 Text ...
2700 -->
2701 ]]>
2703
2706
2708
2710
2711
2715
2717
2718
2723
2725
2727
2730 Form:"
2735 %SDASUFF; "Form End. "
2736 >
2738
2739
2740
2741
2743
2746
2747
2759
2760
2761
2762
2763
2764
2765
2766
2767
2769
2770 Select #AttVal(Multiple)"
2777 >
2779
2780
2781
2782
2784
2785
2793
2794
2795
2797
2798
2806
2807
2808
2809
2811 ]]>
2813
2815
2817 ]]>
2818
2820
2822
2824
2826
2827
2830
2832
2833 " >
2838
2839
2840
2841
2842
2843
2844
2846
2847 [Document is indexed/searchable.]">
2851
2853
2854
2857
2858
2860
2861
2864
2865
2867
2868
2873
2874
2875
2876
2878
2880
2882 ]]>
2883
2885
2886
2888
2893
2895 9.2. Strict HTML DTD
2897 This document type declaration refers to the HTML DTD with the
2898 `HTML.Recommended' entity defined as `INCLUDE' rather than
2899 IGNORE; that is, it refers to the more structurally rigid
2900 definition of HTML.
2902
2912
2919
2920 ...
2921
2922 --
2923 >
2925
2926
2928
2929 %html;
2931 9.3. Level 1 HTML DTD
2933 This document type declaration refers to the HTML DTD with the
2934 `HTML.Forms' entity defined as `IGNORE' rather than `INCLUDE'.
2935 Documents which contain