How to Get Online 1996 Spring

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This document has been altered to only include the tag definitions by Nombas. It was derived from the html 2.0 spec Network Working Group T. Berners-Lee Request for Comments: 1866 MIT/W3C Category: Standards Track D. Connolly November 1995 Hypertext Markup Language - 2.0 HTML has been in use by the World Wide Web (WWW) global information initiative since 1990. This specification roughly corresponds to the capabilities of HTML in common use prior to June 1994. HTML is an application of ISO Standard 8879:1986 Information Processing Text and Office Systems; Standard Generalized Markup Language (SGML). 1. Introduction The HyperText Markup Language (HTML) is a simple data format used to create hypertext documents that are portable from one platform to another. HTML documents are SGML documents with generic semantics that are appropriate for representing information from a wide range of domains. 3.2.2. Tags Tags delimit elements such as headings, paragraphs, lists, character highlighting, and links. Most HTML elements are identified in a document as a start-tag, which gives the element name and attributes, followed by the content, followed by the end tag. Start-tags are delimited by `<' and `>'; end tags are delimited by `</' and `>'. An example is: <H1>This is a Heading</H1> Some elements only have a start-tag without an end-tag. For example, to create a line break, use the `<BR>' tag. Additionally, the end tags of some other elements, such as Paragraph (`</P>'), List Item (`</LI>'), Definition Term (`</DT>'), and Definition Description (`</DD>') elements, may be omitted. 5. Document Structure An HTML document is a tree of elements, including a head and body, headings, paragraphs, lists, etc. Form elements are discussed in 8, "Forms". The HTML document element consists of a head and a body, much like a memo or a mail message. The head contains the title and optional elements. The body is a text flow consisting of paragraphs, lists, and other elements. 5.2. Head: HEAD The head of an HTML document is an unordered collection of information about the document. For example: <!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN"> <HEAD> <TITLE>Introduction to HTML</TITLE> </HEAD> ... 5.2.1. Title: TITLE Every HTML document must contain a <TITLE> element. The title should identify the contents of the document in a global context. A short title, such as "Introduction" may be meaningless out of context. A title such as "Introduction to HTML Elements" is more appropriate. NOTE - The length of a title is not limited; however, long titles may be truncated in some applications. To minimize this possibility, titles should be fewer than 64 characters. A user agent may display the title of a document in a history list or as a label for the window displaying the document. This differs from headings (5.4, "Headings: H1 ... H6"), which are typically displayed within the body text flow. 5.2.2. Base Address: BASE The optional <BASE> element provides a base address for interpreting relative URLs when the document is read out of context (see 7, "Hyperlinks"). The value of the HREF attribute must be an absolute URI. 5.2.3. Keyword Index: ISINDEX The <ISINDEX> element indicates that the user agent should allow the user to search an index by giving keywords. See 7.5, "Queries and Indexes" for details. 5.2.4. Link: LINK The <LINK> element represents a hyperlink (see 7, "Hyperlinks"). Any number of LINK elements may occur in the <HEAD> element of an HTML document. It has the same attributes as the <A> element (see 5.7.3, "Anchor: A"). The <LINK> element is typically used to indicate authorship, related indexes and glossaries, older or more recent versions, document hierarchy, associated resources such as style sheets, etc. 5.2.5. Associated Meta-information: META The <META> element is an extensible container for use in identifying specialized document meta-information. Meta-information has two main functions: * to provide a means to discover that the data set exists and how it might be obtained or accessed; and * to document the content, quality, and features of a data set, indicating its fitness for use. Each <META> element specifies a name/value pair. If multiple META elements are provided with the same name, their combined contents-- concatenated as a comma-separated list--is the value associated with that name. NOTE - The <META> element should not be used where a specific element, such as <TITLE>, would be more appropriate. Rather than a <META> element with a URI as the value of the CONTENT attribute, use a <LINK> element. HTTP servers may read the content of the document <HEAD> to generate header fields corresponding to any elements defining a value for the attribute HTTP-EQUIV. NOTE - The method by which the server extracts document meta-information is unspecified and not mandatory. The <META> element only provides an extensible mechanism for identifying and embedding document meta-information -- how it may be used is up to the individual server implementation and the HTML user agent. Attributes of the META element: HTTP-EQUIV binds the element to an HTTP header field. An HTTP server may use this information to process the document. In particular, it may include a header field in the responses to requests for this document: the header name is taken from the HTTP-EQUIV attribute value, and the header value is taken from the value of the CONTENT attribute. HTTP header names are not case sensitive. NAME specifies the name of the name/value pair. If not present, HTTP-EQUIV gives the name. CONTENT specifies the value of the name/value pair. Examples If the document contains: <META HTTP-EQUIV="Expires" CONTENT="Tue, 04 Dec 1993 21:29:02 GMT"> <meta http-equiv="Keywords" CONTENT="Fred"> <META HTTP-EQUIV="Reply-to" content="fielding@ics.uci.edu (Roy Fielding)"> <Meta Http-equiv="Keywords" CONTENT="Barney"> then the server may include the following header fields: Expires: Tue, 04 Dec 1993 21:29:02 GMT Keywords: Fred, Barney Reply-to: fielding@ics.uci.edu (Roy Fielding) as part of the HTTP response to a `GET' or `HEAD' request for that document. An HTTP server must not use the <META> element to form an HTTP response header unless the HTTP-EQUIV attribute is present. An HTTP server may disregard any <META> elements that specify information controlled by the HTTP server, for example `Server', `Date', and `Last-modified'. 5.3. Body: BODY The <BODY> element contains the text flow of the document, including headings, paragraphs, lists, etc. For example: <BODY> <h1>Important Stuff</h1> <p>Explanation about important stuff... </BODY> 5.4. Headings: H1 ... H6 The six heading elements, <H1> through <H6>, denote section headings. Although the order and occurrence of headings is not constrained by the HTML DTD, documents should not skip levels (for example, from H1 to H3), as converting such documents to other representations is often problematic. Example of use: <H1>This is a heading</H1> Here is some text <H2>Second level heading</H2> Here is some more text. Typical renderings are: H1 Bold, very-large font, centered. One or two blank lines above and below. H2 Bold, large font, flush-left. One or two blank lines above and below. H3 Italic, large font, slightly indented from the left margin. One or two blank lines above and below. H4 Bold, normal font, indented more than H3. One blank line above and below. H5 Italic, normal font, indented as H4. One blank line above. H6 Bold, indented same as normal text, more than H5. One blank line above. 5.5. Block Structuring Elements Block structuring elements include paragraphs, lists, and block quotes. They must not contain heading elements, but they may contain phrase markup, and in some cases, they may be nested. 5.5.1. Paragraph: P The <P> element indicates a paragraph. The exact indentation, leading space, etc. of a paragraph is not specified and may be a function of other tags, style sheets, etc. Typically, paragraphs are surrounded by a vertical space of one line or half a line. The first line in a paragraph is indented in some cases. Example of use: <H1>This Heading Precedes the Paragraph</H1> <P>This is the text of the first paragraph. <P>This is the text of the second paragraph. Although you do not need to start paragraphs on new lines, maintaining this convention facilitates document maintenance.</P> <P>This is the text of a third paragraph.</P> 5.5.2. Preformatted Text: PRE The <PRE> element represents a character cell block of text and is suitable for text that has been formatted for a monospaced font. The <PRE> tag may be used with the optional WIDTH attribute. The WIDTH attribute specifies the maximum number of characters for a line and allows the HTML user agent to select a suitable font and indentation. Within preformatted text: * Line breaks within the text are rendered as a move to the beginning of the next line. NOTE - References to the "beginning of a new line" do not imply that the renderer is forbidden from using a constant left indent for rendering preformatted text. The left indent may be constrained by the width required. * Anchor elements and phrase markup may be used. NOTE - Constraints on the processing of <PRE> content may limit or prevent the ability of the HTML user agent to faithfully render phrase markup. * Elements that define paragraph formatting (headings, address, etc.) must not be used. NOTE - Some historical documents contain <P> tags in <PRE> elements. User agents are encouraged to treat this as a line break. A <P> tag followed by a newline character should produce only one line break, not a line break plus a blank line. * The horizontal tab character (code position 9 in the HTML document character set) must be interpreted as the smallest positive nonzero number of spaces which will leave the number of characters so far on the line as a multiple of 8. Documents should not contain tab characters, as they are not supported consistently. Example of use: <PRE> Line 1. Line 2 is to the right of line 1. <a href="abc">abc</a> Line 3 aligns with line 2. <a href="def">def</a> </PRE> 5.5.2.1. Example and Listing: XMP, LISTING The <XMP> and <LISTING> elements are similar to the <PRE> element, but they have a different syntax. Their content is declared as CDATA, which means that no markup except the end-tag open delimiter-in- context is recognized (see 9.6 "Delimiter Recognition" of [SGML]). NOTE - In a previous draft of the HTML specification, the syntax of <XMP> and <LISTING> elements allowed closing tags to be treated as data characters, as long as the tag name was not <XMP> or <LISTING>, respectively. Since CDATA declared content has a number of unfortunate interactions with processing techniques and tends to be used and implemented inconsistently, HTML documents should not contain <XMP> nor <LISTING> elements -- the <PRE> tag is more expressive and more consistently supported. The <LISTING> element should be rendered so that at least 132 characters fit on a line. The <XMP> element should be rendered so that at least 80 characters fit on a line but is otherwise identical to the <LISTING> element. NOTE - In a previous draft, HTML included a <PLAINTEXT> element that is similar to the <LISTING> element, except that there is no closing tag: all characters after the <PLAINTEXT> start-tag are data. 5.5.3. Address: ADDRESS The <ADDRESS> element contains such information as address, signature and authorship, often at the beginning or end of the body of a document. Typically, the <ADDRESS> element is rendered in an italic typeface and may be indented. Example of use: <ADDRESS> Newsletter editor<BR> J.R. Brown<BR> JimquickPost News, Jimquick, CT 01234<BR> Tel (123) 456 7890 </ADDRESS> 5.5.4. Block Quote: BLOCKQUOTE The <BLOCKQUOTE> element contains text quoted from another source. A typical rendering might be a slight extra left and right indent, and/or italic font. The <BLOCKQUOTE> typically provides space above and below the quote. Single-font rendition may reflect the quotation style of Internet mail by putting a vertical line of graphic characters, such as the greater than symbol (>), in the left margin. Example of use: I think the play ends <BLOCKQUOTE> <P>Soft you now, the fair Ophelia. Nymph, in thy orisons, be all my sins remembered. </BLOCKQUOTE> but I am not sure. 5.6. List Elements HTML includes a number of list elements. They may be used in combination; for example, a <OL> may be nested in an <LI> element of a <UL>. The COMPACT attribute suggests that a compact rendering be used. 5.6.1. Unordered List: UL, LI The <UL> represents a list of items -- typically rendered as a bulleted list. The content of a <UL> element is a sequence of <LI> elements. For example: <UL> <LI>First list item <LI>Second list item <p>second paragraph of second item <LI>Third list item </UL> 5.6.2. Ordered List: OL The <OL> element represents an ordered list of items, sorted by sequence or order of importance. It is typically rendered as a numbered list. The content of a <OL> element is a sequence of <LI> elements. For example: <OL> <LI>Click the Web button to open URI window. <LI>Enter the URI number in the text field of the Open URI window. The Web document you specified is displayed. <ol> <li>substep 1 <li>substep 2 </ol> <LI>Click highlighted text to move from one link to another. </OL> 5.6.3. Directory List: DIR The <DIR> element is similar to the <UL> element. It represents a list of short items, typically up to 20 characters each. Items in a directory list may be arranged in columns, typically 24 characters wide. The content of a <DIR> element is a sequence of <LI> elements. Nested block elements are not allowed in the content of <DIR> elements. For example: <DIR> <LI>A-H<LI>I-M <LI>M-R<LI>S-Z </DIR> 5.6.4. Menu List: MENU The <MENU> element is a list of items with typically one line per item. The menu list style is typically more compact than the style of an unordered list. The content of a <MENU> element is a sequence of <LI> elements. Nested block elements are not allowed in the content of <MENU> elements. For example: <MENU> <LI>First item in the list. <LI>Second item in the list. <LI>Third item in the list. </MENU> 5.6.5. Definition List: DL, DT, DD A definition list is a list of terms and corresponding definitions. Definition lists are typically formatted with the term flush-left and the definition, formatted paragraph style, indented after the term. The content of a <DL> element is a sequence of <DT> elements and/or <DD> elements, usually in pairs. Multiple <DT> may be paired with a single <DD> element. Documents should not contain multiple consecutive <DD> elements. Example of use: <DL> <DT>Term<DD>This is the definition of the first term. <DT>Term<DD>This is the definition of the second term. </DL> If the DT term does not fit in the DT column (typically one third of the display area), it may be extended across the page with the DD section moved to the next line, or it may be wrapped onto successive lines of the left hand column. The optional COMPACT attribute suggests that a compact rendering be used, because the list items are small and/or the entire list is large. Unless the COMPACT attribute is present, an HTML user agent may leave white space between successive DT, DD pairs. The COMPACT attribute may also reduce the width of the left-hand (DT) column. <DL COMPACT> <DT>Term<DD>This is the first definition in compact format. <DT>Term<DD>This is the second definition in compact format. </DL>