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--------------------------------------------------------------------------------
1 HTML Working Group T. Berners-Lee
2 INTERNET-DRAFT MIT/W3C
3 D. Connolly
4 Expires: In six months August 8, 1995
6 Hypertext Markup Language - 2.0
8 Status of this Memo
10 This document is an Internet-Draft. Internet-Drafts are working
11 documents of the Internet Engineering Task Force (IETF), its areas, and
12 its working groups. Note that other groups may also distribute working
13 documents as Internet-Drafts.
15 Internet-Drafts are draft documents valid for a maximum of six months
16 and may be updated, replaced, or obsoleted by other documents at any
17 time. It is inappropriate to use Internet-Drafts as reference material
18 or to cite them other than as ``work in progress.''
20 To learn the current status of any Internet-Draft, please check the
21 1id-abstracts.txt listing contained in the Internet-Drafts Shadow
22 Directories on ftp.is.co.za (Africa), nic.nordu.net (Europe),
23 munnari.oz.au (Pacific Rim), ds.internic.net (US East Coast), or
24 ftp.isi.edu (US West Coast).
26 Distribution of this document is unlimited. Please send comments to the
27 HTML working group (HTML-WG) of the Internet Engineering Task Force
28 (IETF) at . Discussions of the group are archived at
29 .
31 ABSTRACT
33 The Hypertext Markup Language (HTML) is a simple markup language
34 used to create hypertext documents that are platform
35 independent. HTML documents are SGML documents with generic
36 semantics that are appropriate for representing information from
37 a wide range of domains. HTML markup can represent hypertext
38 news, mail, documentation, and hypermedia; menus of options;
39 database query results; simple structured documents with
40 in-lined graphics; and hypertext views of existing bodies of
41 information.
43 HTML has been in use by the World Wide Web (WWW) global
44 information initiative since 1990. This specification roughly
45 corresponds to the capabilities of HTML in common use prior to
46 June 1994. HTML is an application of ISO Standard 8879:1986
47 Information Processing Text and Office Systems; Standard
48 Generalized Markup Language (SGML).
50 The `text/html' Internet Media Type (RFC 1590) and MIME Content
51 Type (RFC 1521) is defined by this specification.
53 CONTENTS
55 1 Introduction .......................................... 3
56 1.1 Scope ................................................. 3
57 1.2 Conformance ........................................... 3
58 2 Terms ................................................. 5
59 3 HTML as an Application of SGML ........................ 9
60 3.1 SGML Documents ........................................ 9
61 3.2 HTML Lexical Syntax .................................. 11
62 3.3 HTML Public Text Identifiers ......................... 15
63 3.4 Example HTML Document ................................ 16
64 4 HTML as an Internet Media Type ....................... 16
65 4.1 text/html media type ................................. 16
66 4.2 HTML Document Representation ......................... 17
67 5 Document Structure ................................... 18
68 5.1 Document Element: HTML ............................... 19
69 5.2 Head: HEAD ........................................... 19
70 5.3 Body: BODY ........................................... 22
71 5.4 Headings: H1 ... H6 .................................. 22
72 5.5 Block Structuring Elements ........................... 23
73 5.6 List Elements ........................................ 25
74 5.7 Phrase Markup ........................................ 28
75 5.8 Line Break: BR ....................................... 31
76 5.9 Horizontal Rule: HR .................................. 31
77 5.10 Image: IMG ........................................... 31
78 6 Characters, Words, and Paragraphs .................... 33
79 6.1 The HTML Document Character Set ...................... 33
80 7 Hyperlinks ........................................... 34
81 7.1 Accessing Resources .................................. 34
82 7.2 Activation of Hyperlinks ............................. 35
83 7.3 Simultaneous Presentation of Image Resources ......... 35
84 7.4 Fragment Identifiers ................................. 36
85 7.5 Queries and Indexes .................................. 36
86 7.6 Image Maps ........................................... 37
87 8 Forms ................................................ 37
88 8.1 Form Elements ........................................ 37
89 8.2 Form Submission ...................................... 42
90 9 HTML Public Text ..................................... 45
91 9.1 HTML DTD ............................................. 46
92 9.2 Strict HTML DTD ...................................... 57
93 9.3 Level 1 HTML DTD ..................................... 57
94 9.4 Strict Level 1 HTML DTD .............................. 58
95 9.5 SGML Declaration for HTML ............................ 59
96 9.6 Sample SGML Open Entity Catalog for HTML ............. 61
97 9.7 Character Entity Sets ................................ 62
98 10 Security Considerations .............................. 64
99 11 References ........................................... 64
100 12 Acknowledgments ...................................... 66
101 12.1 Authors' Addresses ................................... 66
102 13 The HTML Coded Character Set ......................... 66
103 14 Proposed Entities .................................... 69
105 1. Introduction
107 The HyperText Markup Language (HTML) is a simple data format
108 used to create hypertext documents that are portable from one
109 platform to another. HTML documents are SGML documents with
110 generic semantics that are appropriate for representing
111 information from a wide range of domains.
113 As HTML is an application of SGML, this specification assumes a
114 working knowledge of [SGML].
116 1.1. Scope
118 HTML has been in use by the World-Wide Web (WWW) global
119 information initiative since 1990. This specification
120 corresponds to the capabilities of HTML in common use prior to
121 June 1994 and referred to as ``HTML 2.0''.
123 HTML is an application of ISO Standard 8879:1986 _Information
124 Processing Text and Office Systems; Standard Generalized Markup
125 Language_ (SGML). The HTML Document Type Definition (DTD) is a
126 formal definition of the HTML syntax in terms of SGML.
128 This specification also defines HTML as an Internet Media
129 Type[IMEDIA] and MIME Content Type[MIME] called `text/html'. As
130 such, it defines the semantics of the HTML syntax and how that
131 syntax should be interpreted by user agents.
133 1.2. Conformance
135 This specification governs the syntax of HTML documents and
136 aspects of the behavior of HTML user agents.
138 1.2.1. Documents
140 A document is a conforming HTML document if:
142 * It is a conforming SGML document, and it conforms to the
143 HTML DTD (see 9.1, "HTML DTD").
145 NOTE - There are a number of syntactic idioms that
146 are not supported or are supported inconsistently in
147 some historical user agent implementations. These
148 idioms are identified in notes like this throughout
149 this specification.
151 * It conforms to the application conventions in this
152 specification. For example, the value of the HREF attribute
153 of the element must conform to the URI syntax.
155 * Its document character set includes [ISO-8859-1] and
156 agrees with [ISO-10646]; that is, each code position listed
157 in 13, "The HTML Coded Character Set" is included, and each
158 code position in the document character set is mapped to the
159 same character as [ISO-10646] designates for that code
160 position.
162 NOTE - The document character set is somewhat
163 independent of the character encoding scheme used to
164 represent a document. For example, the `ISO-2022-JP'
165 character encoding scheme can be used for HTML
166 documents, since its repertoire is a subset of the
167 [ISO-10646] repertoire. The critical distinction is
168 that numeric character references agree with
169 [ISO-10646] regardless of how the document is
170 encoded.
172 1.2.2. Feature Test Entities
174 The HTML DTD defines a standard HTML document type and several
175 variations, by way of feature test entities. Feature test
176 entities are declarations in the HTML DTD that control the
177 inclusion or exclusion of portions of the DTD.
179 HTML.Recommended
180 Certain features of the language are necessary for
181 compatibility with widespread usage, but they may
182 compromise the structural integrity of a document. This
183 feature test entity selects a more prescriptive document
184 type definition that eliminates those features. It is
185 set to `IGNORE' by default.
187 For example, in order to preserve the structure of a
188 document, an editing user agent may translate HTML
189 documents to the recommended subset, or it may require
190 that the documents be in the recommended subset for
191 import.
193 HTML.Deprecated
194 Certain features of the language are necessary for
195 compatibility with earlier versions of the
196 specification, but they tend to be used and implemented
197 inconsistently, and their use is deprecated. This
198 feature test entity enables a document type definition
199 that allows these features. It is set to `INCLUDE' by
200 default.
202 Documents generated by translation software or editing
203 software should not contain deprecated idioms.
205 1.2.3. User Agents
207 An HTML user agent conforms to this specification if:
209 * It parses the characters of an HTML document into data
210 characters and markup according to [SGML].
212 NOTE - In the interest of robustness and
213 extensibility, there are a number of widely deployed
214 conventions for handling non-conforming documents.
215 See 4.2.1, "Undeclared Markup Error Handling" for
216 details.
218 * It supports the `ISO-8859-1' character encoding scheme and
219 processes each character in the ISO Latin Alphabet No. 1 as
220 specified in 6.1, "The HTML Document Character Set".
222 NOTE - To support non-western writing systems, HTML
223 user agents are encouraged to support
224 `ISO-10646-UCS-2' or similar character encoding
225 schemes and as much of the character repertoire of
226 [ISO-10646] as is practical.
228 * It behaves identically for documents whose parsed token
229 sequences are identical.
231 For example, comments and the whitespace in tags disappear
232 during tokenization, and hence they do not influence the
233 behavior of conforming user agents.
235 * It allows the user to traverse (or at least attempt to
236 traverse, resources permitting) all hyperlinks from
237 elements in an HTML document.
239 An HTML user agent is a level 2 user agent if, additionally:
241 * It allows the user to express all form field values
242 specified in an HTML document and to (attempt to) submit the
243 values as requests to information services.
245 2. Terms
247 absolute URI
248 a URI in absolute form; for example, as per [URL]
250 anchor
251 one of two ends of a hyperlink; typically, a phrase
252 marked as an element.
254 base URI
255 an absolute URI used in combination with a relative URI
256 to determine another absolute URI.
258 character
259 An atom of information, for example a letter or a digit.
260 Graphic characters have associated glyphs, where as
261 control characters have associated processing semantics.
263 character encoding
264 scheme
265 A function whose domain is the set of sequences of
266 octets, and whose range is the set of sequences of
267 characters from a character repertoire; that is, a
268 sequence of octets and a character encoding scheme
269 determines a sequence of characters.
271 character repertoire
272 A finite set of characters; e.g. the range of a coded
273 character set.
275 code position
276 An integer. A coded character set and a code position
277 from its domain determine a character.
279 coded character set
280 A function whose domain is a subset of the integers and
281 whose range is a character repertoire. That is, for some
282 set of integers (usually of the form {0, 1, 2, ..., N}
283 ), a coded character set and an integer in that set
284 determine a character. Conversely, a character and a
285 coded character set determine the character's code
286 position (or, in rare cases, a few code positions).
288 conforming HTML user
289 agent
290 A user agent that conforms to this specification in its
291 processing of the Internet Media Type `text/html'.
293 data character
294 Characters other than markup, which make up the content
295 of elements.
297 document character set
298 a coded character set whose range includes all
299 characters used in a document. Every SGML document has
300 exactly one document character set. Numeric character
301 references are resolved via the document character set.
303 DTD
304 document type definition. Rules that apply SGML to the
305 markup of documents of a particular type, including a
306 set of element and entity declarations. [SGML]
308 element
309 A component of the hierarchical structure defined by a
310 document type definition; it is identified in a document
311 instance by descriptive markup, usually a start-tag and
312 end-tag. [SGML]
314 end-tag
315 Descriptive markup that identifies the end of an
316 element. [SGML]
318 entity
319 data with an associated notation or interpretation; for
320 example, a sequence of octets associated with an
321 Internet Media Type. [SGML]
323 fragment identifier
324 the portion of an HREF attribute value following the `#'
325 character which modifies the presentation of the
326 destination of a hyperlink.
328 form data set
329 a sequence of name/value pairs; the names are given by
330 an HTML document and the values are given by a user.
332 HTML document
333 An SGML document conforming to this document type
334 definition.
336 hyperlink
337 a relationship between two anchors, called the tail and
338 the head.
340 markup
341 Syntactically delimited characters added to the data of
342 a document to represent its structure. There are four
343 different kinds of markup: descriptive markup (tags),
344 references, markup declarations, and processing
345 instructions. [SGML]
347 may
348 A document or user interface is conforming whether this
349 statement applies or not.
351 media type
352 an Internet Media Type, as per [IMEDIA].
354 message entity
355 a head and body. The head is a collection of name/value
356 fields, and the body is a sequence of octets. The head
357 defines the content type and content transfer encoding
358 of the body. [MIME]
360 minimally conforming
361 HTML user agent
362 A user agent that conforms to this specification except
363 for form processing. It may only process level 1 HTML
364 documents.
366 must
367 Documents or user agents in conflict with this statement
368 are not conforming.
370 numeric character
371 reference
372 markup that refers to a character by its code position
373 in the document character set.
375 SGML document
376 A sequence of characters organized physically as a set
377 of entities and logically into a hierarchy of elements.
378 An SGML document consists of data characters and markup;
379 the markup describes the structure of the information
380 and an instance of that structure. [SGML]
382 shall
383 If a document or user agent conflicts with this
384 statement, it does not conform to this specification.
386 should
387 If a document or user agent conflicts with this
388 statement, undesirable results may occur in practice
389 even though it conforms to this specification.
391 start-tag
392 Descriptive markup that identifies the start of an
393 element and specifies its generic identifier and
394 attributes. [SGML]
396 syntax-reference
397 character set
398 A coded character set whose range includes all
399 characters used for markup; e.g. name characters and
400 delimiter characters.
402 tag
403 Markup that delimits an element. A tag includes a name
404 which refers to an element declaration in the DTD, and
405 may include attributes. [SGML]
407 text entity
408 A finite sequence of characters. A text entity typically
409 takes the form of a sequence of octets with some
410 associated character encoding scheme, transmitted over
411 the network or stored in a file. [SGML]
413 typical
414 Typical processing is described for many elements. This
415 is not a mandatory part of the specification but is
416 given as guidance for designers and to help explain the
417 uses for which the elements were intended.
419 URI
420 A Uniform Resource Identifier is a formatted string that
421 serves as an identifier for a resource, typically on the
422 Internet. URIs are used in HTML to identify the anchors
423 of hyperlinks. URIs in common practice include Uniform
424 Resource Locators (URLs)[URL] and Relative URLs
425 [RELURL].
427 user agent
428 A component of a distributed system that presents an
429 interface and processes requests on behalf of a user;
430 for example, a www browser or a mail user agent.
432 WWW
433 The World-Wide Web is a hypertext-based, distributed
434 information system created by researchers at CERN in
435 Switzerland. Parsing Example
483 Some text. *wow*
485 An HTML user agent should use the SGML declaration that is given
486 in 9.5, "SGML Declaration for HTML". According to its document
487 character set, `*' refers to an asterisk character, `*'.
489 The instance above is regarded as the following sequence of
490 terminals:
492 1. start-tag: TITLE
494 2. data characters: ``Parsing Example''
496 3. end-tag: TITLE
498 4. start-tag: P
500 5. data characters ``Some text. ''
502 6. start-tag: EM
504 7. data characters: ``*wow*''
506 8. end-tag: EM
508 9. end-tag: P
510 The start symbol of the DTD grammar is HTML, and the productions
511 are given in the public text identified by `-//IETF//DTD HTML
512 2.0//EN' (9.1, "HTML DTD"). The terminals above parse as:
514 HTML
515 |
516 \-HEAD
517 | |
518 | \-TITLE
519 | |
520 | \-
521 | |
522 | \-"Parsing Example"
523 | |
524 | \-
525 |
526 \-BODY
527 |
528 \-P
529 |
530 \-
531 |
532 \-"Some text. "
533 |
534 \-EM
535 | |
536 | \-
537 | |
538 | \-"*wow*"
539 | |
540 | \-
541 |
542 \-
544 Some of the elements are delimited explicity by tags, while the
545 boundaries of others are inferred. The element contains a
546 element and a element. The contains
547 , which is explicitly delimited by start- and end-tags.
549 3.2. HTML Lexical Syntax
551 SGML specifies an abstract syntax and a reference concrete
552 syntax. Aside from certain quantities and capacities (e.g. the
553 limit on the length of a name), all HTML documents use the
554 reference concrete syntax. In particular, all markup characters
555 are in the repertoire of [ISO-646]. Data characters are drawn
556 from the document character set (see 6, "Characters, Words, and
557 Paragraphs").
559 A complete discussion of SGML parsing, e.g. the mapping of a
560 sequence of characters to a sequence of tags and data, is left
561 to the SGML standard[SGML]. This section is only a summary.
563 3.2.1. Data Characters
565 Any sequence of characters that do not constitute markup (see
566 9.6 ``Delimiter Recognition'' of [SGML]) are mapped directly to
567 strings of data characters. Some markup also maps to data
568 character strings. Numeric character references map to
569 single-character strings, via the document character set. Each
570 reference to one of the general entities defined in the HTML DTD
571 maps to a single-character string.
573 For example,
575 abc<def => "abc","<","def"
576 abc<def => "abc","<","def"
578 The terminating semicolon on entity or numeric character
579 references is only necessary when the character following the
580 reference would otherwise be recognized as part of the name (see
581 9.4.5 ``Reference End'' in [SGML]).
583 abc < def => "abc ","<"," def"
584 abc < def => "abc ","<"," def"
586 An ampersand is only recognized as markup when it is followed by
587 a letter or a `#' and a digit:
589 abc & lt def => "abc & lt def"
590 abc &# 60 def => "abc &# 60 def"
592 A useful technique for translating plain text to HTML is to
593 replace each '<', '&', and '>' by an entity reference or numeric
594 character reference as follows:
596 ENTITY NUMERIC
597 CHARACTER REFERENCE CHAR REF CHARACTER DESCRIPTION
598 --------- ---------- ----------- ---------------------
599 & & & Ampersand
600 < < < Less than
601 > > > Greater than
603 NOTE - There are SGML mechanisms, CDATA and RCDATA
604 declared content, that allow most `<', `>', and `&'
605 characters to be entered without the use of entity
606 references. Because these mechanisms tend to be used and
607 implemented inconsistently, and because they conflict
608 with techniques for reducing HTML to 7 bit ASCII for
609 transport, they are deprecated in this version of HTML.
610 See 5.5.2.1, "Example and Listing: XMP, LISTING".
612 3.2.2. Tags
614 Tags delimit elements such as headings, paragraphs, lists,
615 character highlighting, and links. Most HTML elements are
616 identified in a document as a start-tag, which gives the element
617 name and attributes, followed by the content, followed by the
618 end tag. Start-tags are delimited by `<' and `>'; end tags are
619 delimited by `</' and `>'. An example is:
621 <H1>This is a Heading</H1>
623 Some elements only have a start-tag without an end-tag. For
624 example, to create a line break, you use the `<BR>' tag.
625 Additionally, the end tags of some other elements, such as
626 Paragraph (`</P>'), List Item (`</LI>'), Definition Term
627 (`</DT>'), and Definition Description (`<DD>') elements, may be
628 omitted.
630 The content of an element is a sequence of data character
631 strings and nested elements. Some elements, such as anchors,
632 cannot be nested. Anchors and character highlighting may be put
633 inside other constructs. See the HTML DTD, 9.1, "HTML DTD" for
634 full details.
636 NOTE - The SGML declaration for HTML specifies SHORTTAG
637 YES, which means that there are other valid syntaxes for
638 tags, such as NET tags, `<EM/.../'; empty start tags,
639 `<>'; and empty end-tags, `</>'. Until support for these
640 idioms is widely deployed, their use is strongly
641 discouraged.
643 3.2.3. Names
645 A name consists of a letter followed by letters, digits,
646 periods, or hyphens. The length of a name is limited to 72
647 characters by the `NAMELEN' parameter in the SGML delcaration
648 for HTML, 9.5, "SGML Declaration for HTML". Element and
649 attribute names are not case sensitive, but entity names are.
650 For example, `<BLOCKQUOTE>', `<BlockQuote>', and `<blockquote>'
651 are equivalent, whereas `&' is different from `&'.
653 In a start-tag, the element name must immediately follow the tag
654 open delimiter `<'.
656 3.2.4. Attributes
658 In a start-tag, white space and attributes are allowed between
659 the element name and the closing delimiter. An attribute
660 specification typically consists of an attribute name, an equal
661 sign, and a value, though some attribute specifications may be
662 just a name token. White space is allowed around the equal sign.
664 The value of the attribute may be either:
666 * A string literal, delimited by single quotes or double
667 quotes and not containing any occurrences of the delimiting
668 character.
670 NOTE - Some historical implementations consider any
671 occurrence of the `>' character to signal the end of
672 a tag. For compatibility with such implementations,
673 when `>' appears in an attribute value, it should be
674 represented with a numeric character reference. For
675 example, `<IMG SRC="eq1.jpg" alt="a>b">' should be
676 written `<IMG SRC="eq1.jpg" alt="a>b">' or `<IMG
677 SRC="eq1.jpg" alt="a>b">'.
679 * A name token (a sequence of letters, digits, periods, or
680 hyphens). Name tokens are not case sensitive.
682 NOTE - Some historical implementations allow any
683 character except space or `>' in a name token.
685 In this example, <img> is the element name, src is the attribute
686 name, and `http://host/dir/file.gif' is the attribute value:
688 <img src='http://host/dir/file.gif'>
690 A useful technique for computing an attribute value literal for
691 a given string is to replace each quote and white space
692 character by an entity reference or numeric character reference
693 as follows:
695 ENTITY NUMERIC
696 CHARACTER REFERENCE CHAR REF CHARACTER DESCRIPTION
697 --------- ---------- ----------- ---------------------
698 HT Tab
699 LF
Line Feed
700 CR
Carriage Return
701 SP Space
702 " " " Quotation mark
703 & & & Ampersand
705 For example:
707 <IMG SRC="image.jpg" alt="First "real" example">
709 The `NAMELEN' parameter in the SGML declaration (9.5, "SGML
710 Declaration for HTML") limits the length of an attribute value
711 to 1024 characters.
713 Attributes such as ISMAP and COMPACT may be written using a
714 minimized syntax (see 7.9.1.2 ``Omitted Attribute Name'' in
715 [SGML]). The markup:
717 <UL COMPACT="compact">
719 can be written using a minimized syntax:
721 <UL COMPACT>
723 NOTE - Some historical implementations only understand
724 the minimized syntax.
726 3.2.5. Comments
728 To include comments in an HTML document, use a comment
729 declaration. A comment declaration consists of `<!' followed by
730 zero or more comments followed by `>'. Each comment starts with
731 `--' and includes all text up to and including the next
732 occurrence of `--'. In a comment declaration, white space is
733 allowed after each comment, but not before the first comment.
734 The entire comment declaration is ignored.
736 NOTE - Some historical HTML implementations incorrectly
737 consider any `>' character to be the termination of a
738 comment.
740 For example:
742 <!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
743 <HEAD>
744 <TITLE>HTML Comment Example
745
746
747
748
749
750
752 3.3. HTML Public Text Identifiers
754 To identify information as an HTML document conforming to this
755 specification, each document must start with one of the
756 following document type declarations.
758
760 This document type declaration refers to the HTML DTD in 9.1,
761 "HTML DTD".
763 NOTE - If the body of a `text/html' message entity does
764 not begin with a document type declaration, an HTML user
765 agent should infer the above document type declaration.
767
769 This document type declaration also refers to the HTML DTD which
770 appears in 9.1, "HTML DTD".
772
774 This document type declaration refers to the level 1 HTML DTD in
775 9.3, "Level 1 HTML DTD". Form elements must not occur in level 1
776 documents.
778
779
781 These two document type declarations refer to the HTML DTD in
782 9.2, "Strict HTML DTD" and 9.4, "Strict Level 1 HTML DTD". They
783 refer to the more structurally rigid definition of HTML.
785 HTML user agents may support other document types. In
786 particular, they may support other formal public identifiers, or
787 other document types altogether. They may support an internal
788 declaration subset with supplemental entity, element, and other
789 markup declarations.
791 3.4. Example HTML Document
793
794
795
796
797 Structural Example
798
799 First Header
800 This is a paragraph in the example HTML file. Keep in mind
801 that the title does not appear in the document text, but that
802 the header (defined by H1) does.
803
804 - First item in an ordered list.
805
- Second item in an ordered list.
806
807 - Note that lists can be nested;
808
- Whitespace may be used to assist in reading the
809 HTML source.
810
811 - Third item in an ordered list.
812
813 This is an additional paragraph. Technically, end tags are
814 not required for paragraphs, although they are allowed. You can
815 include character highlighting in a paragraph. This sentence
816 of the paragraph is emphasized. Note that the </P>
817 end tag has been omitted.
818
819 
820 Be sure to read these bold instructions.
821
823 4. HTML as an Internet Media Type
825 An HTML user agent allows users to interact with resources which
826 have HTML representations. At a minimum, it must allow users to
827 examine and navigate the content of HTML level 1 documents. HTML
828 user agents should be able to preserve all formatting
829 distinctions represented in an HTML document, and be able to
830 simultaneously present resources referred to by IMG elements
831 (they may ignore some formatting distinctions or IMG resources
832 at the request of the user). Level 2 HTML user agents should
833 support form entry and submission.
835 4.1. text/html media type
837 This specification defines the Internet Media Type[IMEDIA]
838 (formerly referred to as the Content Type[MIME]) called
839 `text/html'. The following is to be registered with [IANA].
841 Media Type name
842 text
844 Media subtype name
845 html
847 Required parameters
848 none
850 Optional parameters
851 level, charset
853 Encoding considerations
854 any encoding is allowed
856 Security considerations
857 see 10, "Security Considerations"
859 The optional parameters are defined as follows:
861 Level
862 The level parameter specifies the feature set used in
863 the document. The level is an integer number, implying
864 that any features of same or lower level may be present
865 in the document. Level 1 is all features defined in this
866 specification except those that require the
2279 The initial state of the form data set is:
2281 name
2282 ``''
2284 gender
2285 ``male''
2287 family
2288 ``''
2290 other
2291 ``''
2293 nickname
2294 ``''
2296 Note that the radio input has an initial value, while the
2297 checkbox has none.
2299 The user might edit the fields and request that the form be
2300 submitted. At that point, suppose the values are:
2302 name
2303 ``John Doe''
2305 gender
2306 ``male''
2308 family
2309 ``5''
2311 city
2312 ``kent''
2314 city
2315 ``miami''
2317 other
2318 ``abc\ndef''
2320 nickname
2321 ``J&D''
2323 The user agent then conducts an HTTP POST transaction using the
2324 URI `http://www.w3.org/sample'. The message body would be
2325 (ignore the line break):
2327 name=John+Doe&gender=male&family=5&city=kent&city=miami&
2328 other=abc%0D%0Adef&nickname=J%26D
2330 9. HTML Public Text
2331 9.1. HTML DTD
2333 This is the Document Type Definition for the HyperText Markup
2334 Language, level 2.
2336
2348
2354
2355 ...
2356
2357 --
2358 >
2360
2362
2371
2373 ]]>
2375
2384
2390
2396
2398
2403
2407
2409
2411
2413
2415
2417 %ISOlat1;
2419
2420
2421
2422
2424
2426
2443
2445
2447
2449
2451
2454
2456
2460
2462
2464
2465
2468
2471
2475
2476
2477
2479
2480
2481
2482
2483
2484
2485
2487
2489 ]]>
2490
2492
2493
2497
2499
2501
2503
2511 Heading
2514 is preferred to
2515 Heading
2516 -->
2517 ]]>
2519
2521
2522 "
2527 >
2528
2529
2530
2531
2532
2533
2534
2535
2537
2539
2540 #AttVal(Alt)"
2546 >
2548
2549
2550
2551
2552
2554
2556
2557
2561
2563
2565
2566
2570
2572
2573
2576
2579
2582
2585
2588
2592
2593
2594
2595
2596
2597
2599
2601
2603 ]]>
2605
2607
2609 ]]>
2611
2613
2617
2619
2620
2621
2626
2627
2629
2637
2638
2642
2647
2648
2650
2651
2653
2656 ]]>
2658
2660
2661
2667
2668
2672
2673
2677
2678
2679
2680
2682
2683
2687
2691
2692
2693
2694
2696
2697 Directory"
2701 >
2702 Menu"
2706 >
2708
2709
2710
2711
2713
2714
2718
2720
2722 Heading
2725 Text ...
2726 is preferred to
2727
Heading
2728 Text ...
2729 -->
2730 ]]>
2732
2735
2737
2739
2740
2744
2746
2747
2752
2753
2755
2758 Form:"
2763 %SDASUFF; "Form End. "
2764 >
2766
2767
2768
2769
2771
2774
2775
2787
2788
2789
2790
2791
2792
2793
2794
2795
2797
2798 Select #AttVal(Multiple)"
2805 >
2807
2808
2809
2810
2812
2813
2821
2822
2823
2825
2826
2834
2835
2836
2837
2839 ]]>
2841
2843
2845 ]]>
2846
2848
2850
2852
2854
2855
2858
2860
2861 " >
2866
2867
2868
2869
2870
2871
2872
2874
2875 [Document is indexed/searchable.]">
2879
2881
2882
2885
2886
2888
2889
2892
2893
2895
2896
2901
2902
2903
2904
2906
2908
2910 ]]>
2911
2912
2913
2915
2920
2922 9.2. Strict HTML DTD
2924 This document type declaration refers to the HTML DTD with the
2925 `HTML.Recommended' entity defined as `INCLUDE' rather than
2926 IGNORE; that is, it refers to the more structurally rigid
2927 definition of HTML.
2929
2940
2947
2948 ...
2949
2950 --
2951 >
2953
2954
2956
2957 %html;
2959 9.3. Level 1 HTML DTD
2961 This document type declaration refers to the HTML DTD with the
2962 `HTML.Forms' entity defined as `IGNORE' rather than `INCLUDE'.
2964 Documents which contain