Description
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HEAD <HEAD></HEAD>
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The HEAD element has no attributes and the start and end tag can always be safely omitted as they can be readily inferred by the parser.
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Information in the HEAD element corresponds to the top part of a memo or mail message. It describes properties of the document such as the title, the document toolbar, and additional meta-information. There is no intended significance to the order of
elements in the document head. Note that the TITLE element is always required. In fact, the minimal HTML 3.0 document consists of the TITLE element alone!
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Within the HEAD element, only certain elements are allowed. Information in the HEAD element may include the following elements (arranged alphabetically):
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BASE <BASE....>
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The BASE element allows the URL of the document itself to be recorded in situations in which the document may be read out of context. URLs within the document may be in a "partial" form relative to this base address. The default base address
is the URL used to retrieve the document.
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For example:
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<base href="http://acme.com/docs/mydoc.html">
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...
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<img src="images/me.gif">,
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which resolves to "http://acme.com/docs/images/me.gif".
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ISINDEX <ISINDEX>
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The ISINDEX element informs the HTML user agent that the document is an index document. As well as reading it, the reader may use a keyword search.
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The URL used for processing queries can be overridden with the HREF attribute. You can also use the PROMPT attribute to change the default prompt supplied by the browser, for example.
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<ISINDEX HREF="phone.db" PROMPT="Enter Surname:">
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LINK <LINK>
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The LINK element indicates a relationship between the document and some other object. A document may have any number of LINK elements.
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The LINK element is empty (does not have a closing tag), but takes the same attributes as the anchor element. The important attributes are:
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REL
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This defines the relationship defined by the link.
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REV
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This defines a reverse relationship. A link from document A to document B with REV=relation expresses the same relationship as a link from B to A with REL=relation. REV=made is sometimes used to identify the document author, either the author's e-mail
address with a mailto URI or a link to the author's home page.
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HREF
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This names an object using the URI notation.
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META <META.....>
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The META element is used within the HEAD element to embed document meta-information not defined by other HTML elements. Such information can be extracted by servers/clients for use in identifying, indexing and cataloging specialized document
meta-information.
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NAME
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Used to name a property such as author and publication date. If absent, the name can be assumed to be the same as the value of HTTP-EQUIV.
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CONTENT
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Used to supply a value for a named property.
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HTTP-EQUIV
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This attribute binds the element to an HTTP response header. If the semantics of the HTTP response header named by this attribute is known, then the contents can be processed based on a well-defined syntactic mapping, whether or not the DTD includes
anything about it. HTTP header names are not case-sensitive. If absent, the NAME attribute should be used to identify this meta-information, and it should not be used within an HTPP response header.
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Examples:
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If the document contains:
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<META HTTP-EQUIV=Expires CONTENT="Tue, 04 Dec 1993 21:29:02 GMT">
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<META HTTP-EQUIV="Keywords" CONTENT="Nanotechnology, Biochemistry">
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>
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<META HTTP-EQUIV="Reply-to" CONTENT="dsr@w3.org (Dave Raggett)"
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The server will include the following response headers:
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Expires: Tue, 04 Dec 1993 21:29:02 GMT
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Keywords: Nanotechnology, Biochemistry
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Reply-to: dsr@w3.org (Dave Raggett)
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NEXTID <NEXTID ...>
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The NEXTID is a parameter read and generated by text editing software to generate unique identifiers. This tag takes a single attribute which is the the next document-wide alpha-numeric identifier to be allocated of the form z123.
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Example: <NEXTID N=Z27>
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RANGE <RANGE...>
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The RANGE element is used to mark a range of the document, for example for highlighting regions of the document matching some search criteria, or which are the subject of an annotation etc. <RANGE CLASS=Search FROM=spot01 UNTIL=spot02>
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ID
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An SGML identifer used to name the range element.
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CLASS
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A character string used to subclass the range element.
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FROM
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References an SGML identifier for an element in the document body. It identifies the start of the marked range.
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UNTIL
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References an SGML identifier for an element in the document body. It identifies the end of the marked range.
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STYLE <STYLE...>
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The STYLE element provides a means for including rendering information using a specified style notation. Information in the STYLE element overrides client defaults and that of linked style sheets. It allows authors to specify overrides, while for the
most part using a generic style sheet, and as such improves the effectiveness of caching schemes for linked style sheets. There is one attribute—NOTATION—which specifies an entity identifying an SGML notation in the HTML 3.0 DTD, for example:
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<style notation=dsssl-lite>
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some dsssl-lite stuff
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</style>
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Stylistic rules will in general match tag names and attribute values for elements in the document body. Context-sensitive rules may be used for such purposes as rendering drop-down capitals for the initial letter in the first paragraph following a
header.
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TITLE <TITLE </TITLE>
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Every HTML document must contain a TITLE element. The title should identify the contents of the document in a global context, and may be used in a history lists and as a label for the window displaying the document. Unlike headings, titles are not
normally displayed in the text of a document itself. The TITLE element must occur within the head of the document, and may not contain anchors, paragraph tags, or highlighting. There may only be one TITLE in any document.
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BODY <BODY ...>
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Within the BODY element, you can structure text into paragraphs, and lists, as well as highlighting phrases and creating links, amongst other things. The BODY element has the following attributes, all of which are optional:
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ID
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LANG
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This is one of the ISO standard language abbreviations, for example, en.uk for the variation of English spoken in the United Kingdom. It can be used by parsers to select language specific choices for quotation marks, ligatures and hypenation rules, and
so on. The language attribute is composed from the two letter language code from ISO 639, optionally followed by a period and a two letter country code from ISO 3166.
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CLASS
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BACKGROUND
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This can be used to specify a URI for an image tile to cover the document background. This provides a way of giving a group of documents a distinctive appearence. Clients may ignore this attribute. It is included here for the benefit of clients that
don't support style sheets. Note that the text color may need to be adjusted to show an adequate contrast with the background.
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Banners <BANNER...>
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The BANNER element is used for corporate logos, navigation aids, disclaimers and other information which shouldn't be scrolled with the rest of the document. It provides an alternative to using the LINK element in the document head to reference an
externally defined banner.
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ID
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LANG
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CLASS
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Divisions <DIV> </DIV>
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The DIV element is used with the CLASS attribute to represent different kinds of containers, such as chapter, section, abstract, or appendix. For example:
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<DIV CLASS=Abstract>
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The Chieftain product range is the white hot hope for the coming year. This report sets out how to position Chieftain against competing products.<P>
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</DIV>
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ID
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LANG
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CLASS
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ALIGN
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The ALIGN attribute can be used to explicitly specify the horizontal alignment of paragraphs within a division:
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align=left Paragraphs are rendered flush left (the default).
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align=center Paragraphs are centered.
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align=right Paragraphs are rendered flush right.
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align=justify Text lines are justified where practical, otherwise this gives the same effect as the default align=left setting.
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NOWRAP
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The NOWRAP attribute is used when you don't want the browser to automatically wrap lines. You can then explicitly specify line breaks in paragrphs using the BR element.
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CLEAR
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This attribute is common to all block-like elements. When text flows around a figure or table in the margin, you sometimes want to start the division below the figure rather than alongside it. The CLEAR attribute allows you to move down
unconditionally:
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clear=left
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move down until left margin is clear
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clear=right
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move down until right margin is clear
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clear=all
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move down until both margins are clear
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Alternatively, you can decide to place the element alongside the figure just so long as there is enough room. The minimum width needed is specified as:
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clear="40 en"
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move down until there is at least 40 en units free
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clear="100 pixels"
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move down until there is at least 100 pixels free
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The style sheet (or browser defaults) may provide default minimum widths for each class of block-like elements.
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Headings <Hx> </Hx>
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HTML defines six levels of headings. A heading element implies all the font changes,
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Where x = 1 - 6 paragraph breaks before and after, and any white space.
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Netscape includes two tags: <NOBR>...</NOBR> and <WBR>. The former turns off wordwrapping between the start and end NOBR tag, while WBR is for the rare case when you want to specify where to break the line if needed. Should HTML 3.0
provide an equivalent mechanism to WBR.
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ID
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LANG
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CLASS
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ALIGN
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CLEAR
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SEQNUM
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A sequence number is associated with each level of header from the top level (H1) to the bottom level (H6). This attribute is used to set the sequence number associated with the header level of the current element to a given number, such as SEQNUM=10.
Normally, the sequence number is initialized to 1 at the beginning of the document and incremented after each header element. It is reset to 1 by any header element of a higher level, such as an H1 header resetting the sequence numbers for H2 to H6. The
style of header numbering is controlled by the style sheet.
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SKIP
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Increments the sequence number before rendering the element. It is used when headers have been left out of the sequence. For instance, SKIP=3 advances the sequence number past 3 omitted items.
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DINGBAT
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Specifies an iconic image to appear preceding the header. The icon is specified as an entity name.
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SRC
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Specifies an image to appear preceding the header. The image is specified as a URI. This attribute may appear together with the MD attribute.
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MD
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Specifies a message digest or cryptographic checksum for the associated graphic specified by the SRC attribute. It is used when you want to be sure that a linked object is indeed the same one that the author intended, and hasn't been modified in any
way. For instance,
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MD="md5:jV2OfH+nnXHU8bnkPAad/mSQlTDZ",
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which specifies an MD5 checksum encoded as a base64 character string. The MD attribute is generally allowed for all elements that support URI-based links.
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NOWRAP
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Paragraphs <P>
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The <P> element is used to define a paragraph. The exact rendering (indentation, leading, and so on) is not defined and may be a function of other tags and style sheets
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ID
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LANG
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CLASS
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ALIGN
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CLEAR
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Line Breaks <BR>
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Line break and tab elements can be used when you need a little more control over how the browser renders the text. The <BR> element is used to force a line break. For example:
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This is the first line<br>
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and this is the second<br>
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and this the third
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ID
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LANG
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CLASS
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CLEAR
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Horizontal Tabs<TAB...>
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The TAB element can be used when you want fine control over the horizontal positioning. The TAB element is used with the <tab id=name> attribute to define named tab stops. Subsequently, you can use the TAB element with the <tab to=name>
attribute to move to he previously defined tab stop. This approach avoids the need to know the font metrics in advance. The TAB element, together with style sheets, allows conversion software to preserve layout information when importing documents created
with conventional word processing software. For example:
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<p><b>noct<tab id=t1>ambulant</b> - walking at night<br>
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<tab to=t1>(from Latin: <i>nox noctis</i> night + <i>ambulare</i> walk)
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ID
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INDENT
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Specifies the number of en units before the tab stop. The en is a typographical unit equal to half the point size. It allows authors to control the leading indent before text; for example, in poetry, one might use: <TAB INDENT=6> to indent six en
units at the start of a line. The INDENT attribute is not meaningful when combined with the TO attribute.
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TO
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Specifies a previously defined tab stop (see ID attribute).
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ALIGN
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DP
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This specifies the character to be used for the decimal point with the ALIGN attribute— for example, dp="." (the default) or dp=",". The default may be altered by the language context, as set by the LANG attribute on enclosing
elements.
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Note: if the specified alignment and tab stop would cause text to overlap preceding text, then the tab element may be treated as a single space character.
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Hypertext Links <A ...> </A>
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The anchor <A> element is used to define the start and/or destination of a hypertext link. In previous versions of HTML, it provided the only means for defining destination anchors within documents, but you can now use any ID attribute as a
destination anchor so that links can now be made to divisions, paragraphs and most other elements. Example:
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The <A HREF="http://www.w3.org/">World Wide Web Organization</A> provides information on Web-related standards, mailing lists, and freeware tools.
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For FIG elements, the anchor element serves a dual role. Non-graphical user agents interpret it as a conventional text-based hypertext link, while graphical user agents interpret the anchor's SHAPE attribute as a graphical hotzone on the figure.
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ID
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LANG
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CLASS
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HREF
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MD
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NAME
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SHAPE
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This attribute is used within figures to define shaped hotzones for graphical hypertext links. Full details of how to use this feature will be given with the description of the figure element. The attribute value is a string taking one of the following
forms:
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"default"
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Used to define a default link for the figure background.
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"circle x, y, r"
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Where x and y define the center, and r specifies the radius.
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"rect x, y, w, h"
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Where x and y define the upper-left corner, and w and h define the width and height, respectively.
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"polygon x1, y1, x2, y2, ..."
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Given n pairs of x, y coordinates, the polygon is closed by a line linking the nth point to the first. Intersecting polygons use the non-zero winding number rule to determine if a point lies inside the polygon.
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If a pointer event occurs in a region where two or more shapes overlap, the distance from the point to the center of gravity of each of the overlapping shapes is computed and the closest one chosen. This feature is useful when you want lots of closely
spaced hotzones, for example over points on a map, because it allows you to use simple shapes without worrying about overlaps.
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Note: The x coordinate increases to the right, and the y coordinate increases downward in the same way as IMG and imagemaps. If both numbers are integers, the coordinates are interpreted as pixel offsets from the upper-left corner of the figure.
Otherwise, the coordinates are interpreted as scaled values in the range 0.0 to 1.0 across the figure. Note the syntax is tolerant of repeated white space characters between tokens.
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TITLE
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This is informational only and describes the object specified with the HREF attribute. It can be used for object types that don't possess titles, such as graphics, plain text, and Gopher menus.
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REL
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REV
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Information Type Elements
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EM <EM> </EM>
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The <EM> element provides typographic emphasis, typically italics. While <EM> and <I> often give the same effect, use <EM> except where it is necessary in the text to refer to the formatting, as in "The italic parts are
mandatory." This will help to ensure consistency between documents from various sources if (for example) the reader prefers to use color in place of italics for emphasis.
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CITE <CITE> </CITE>
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The <CITE> element specifies a citation. Sections tagged with the CITE element is typically rendered in italics.
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STRONG <STRONG> </STRONG>
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The <STRONG> element provides strong typographic emphasis, typically bold.
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CODE <CODE> </CODE>
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The <CODE> element indicates an example of code; typically rendered in a monospaced font. Do not confuse with PRE.
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SAMP <SAMP> </SAMP>
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The <SAMP> element indicates a sequence of literal characters.
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KBD <KBD> </KBD>
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The <KBD> element indicates text typed (keyboarded) by the user. It might typically be used in an instruction manual.
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VAR <VAR> </VAR>
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The <VAR> element indicates a variable name, and might typically be used in an instruction manual.
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DFN <DFN> </DFN>
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The <DFN> element indicates the defining instance of a term.
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Q <Q> </Q>
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The <Q> element is used for a short quotation. It is typically shown enclosed in quotation marks as appropriate to the language context. For English these would be matching double or single quotation marks, alternating for nested quotes. The
language context is set by the LANG attribute.
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LANG <LANG> </LANG>
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The <LANG> element is used to alter the language context when it is inappropriate to do this with other character-level elements.
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AU <AU> </AU>
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The <AU> element indicates the name of an author.
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PERSON <PERSON> </PERSON>
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The <PERSON> element is used for names of people to allow these to be extracted automatically by indexing programs. New in 3.0
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ACRONYM <ACRONYM> </ACRONYM>
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The <ACRONYM> element is used to mark up acronyms.
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ABBREV <ABBREV> </ABBREV>
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The <ABBREV> element is used to mark up abbreviations.
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INS <INS> </INS>
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The <INS> element is used for inserted text, for instance in legal documents.
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DEL <DEL> </DEL>
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The <DEL> is used for deleted text, for instance in legal documents.
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Font Style Elements
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B (Boldface) <B> </B>
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The <B> element specifies that the enclosed text should be displayed in a boldface. If this is not practical, an alternative mapping is allowed.
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I (Italic) <I> </I>
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The <I> element specifies that the enclosed text should be displayed, if practical, in an italic font (or slanted).
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TT (TeleType) <TT> </TT>
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The <TT> element specifies that the enclosed text should be displayed, if practical, in a fixed-pitch typewriter font.
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U (Underline) <U> </U>
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The <U> element specifies that the enclosed text should be displayed, if practical, as underlined. Not widely supported.
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S (Strikethrough) <S> </S>
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The <S> element specifies that the enclosed text should be displayed with a horizontal line striking through the text. If this is not practical, an alternative mapping is allowed.
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BIG (big print) <BIG> </BIG>
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The <BIG> element specifies that the enclosed text should be displayed, if practical, using a big font (compared with the current font).
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SMALL (small print) <SMALL> </SMALL>
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The <SMALL> element specifies that the enclosed text should be displayed, if practical, using a small font (compared with normal text).
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SUB (subscript) <SUB> </SUB>
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The <SUB> element specifies that the enclosed text should be displayed as a subscript, and if practical, using a smaller font (compared with normal text). The ALIGN attribute for SUB is only meaningful within the MATH element.
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SUP (superscript) <SUP> </SUP>
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The <SUP> element specifies that the enclosed text should be displayed as a superscript, and if practical, using a smaller font (compared with normal text). The ALIGN attribute for SUP is only applicable within the MATH element.
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IMG (Image)
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The <IMG> tag is used to incorporate in-line graphics (typically icons or small graphics) into an HTML document. This element is not intended for embedding other HTML text. For large figures with captions and text flow see FIG element.
Example:
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<IMG SRC="tajmahal.gif" ALT="The Taj Mahal">
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Browsers that cannot display inline images ignore the IMG element unless it contains the ALT attribute. Note that some browsers can display (or print) linked graphics but not in-line graphics. If the graphic is essential, you may want to create a link
to it rather than to put it in-line. If the graphic is essentially decorative, then IMG is appropriate.
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ID
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LANG
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CLASS
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SRC
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MD
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WIDTH
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Optional suggested width for the image. By default, this is given in pixels.
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HEIGHT
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Optional suggested height for the image. By default, this is given in pixels.
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UNITS
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This optional attribute specifies the units for the width and height attributes. It is one of: units=pixels (the default) or units=en (half the point size).
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ALIGN
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Take values TOP, MIDDLE, or BOTTOM, defining whether the top or middle or bottom of the graphic should be aligned withthe baseline for the text line in which the IMG element appears. With ALIGN=LEFT, the graphic will float down and over to the current
left margin, and subsequent text will wrap around the right side of the graphic. Likewise for ALIGN=RIGHT, the graphic aligns with the current right margin and, and text wraps around the left. It is inappropriate to use this feature for larger graphics,
which are best represented with the FIG element.
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ALT (alternate text)
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Optional alternative text as an alternative to the graphics for display in text-only environments. The alt text can contain entitiese.g. for accented characters or special symbols, but it can't contain markup. The latter is possible, however, with the
FIG element.
|
|
|
ISMAP
|
|
An imagemap is a graphical map by which users can navigate transparently from one information resource to another. The ISMAP attribute identifies an image as an imagemap. The IMG element can then be used as part of the label for a hypertext link(see the
anchor element). When the user clicks the image, the location clicked is sent to the server designated by thehypertext link. For example:
|
|
|
|
|
<A HREF="http://machine
|
|
|
|
|
/htbin/imagemap/sample">
|
|
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|
|
<IMG SRC="sample.gif" ISMAP></A>
|
|
UL (Unordered List) <UL> <LI> (LI is optional) </UL>
|
|
II
|
An unordered list typically is a bulleted list of items. HTML 3.0 gives you the ability to customize the bullets, to do without bullets and to wrap list items horizontally or vertically for multicolumn lists.
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|
|
|
|
The opening list tag must be <UL>. It is followed by an optional list header (<LH>caption</LH>) and then by the first list item (<LI>). For example:
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|
|
<UL>
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|
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|
|
<LH>Table Fruit</LH>
|
|
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|
|
<LI>apples
|
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|
|
<LI>oranges
|
|
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|
|
<LI>bananas
|
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|
|
|
</UL>
|
|
MENU and DIR <MENU> </MENU> <DIR> </DIR>
|
|
II
|
These elements are superceded by extensions to the UL element. User agents are advised to continue to support them for the sake of legacy documents.
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|
|
ID
|
|
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|
|
LANG
|
|
|
|
|
CLASS
|
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|
CLEAR
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PLAIN
|
|
The presence of this attribute suppresses the display of bullets, such as <UL PLAIN>.
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SRC
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MD
|
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|
DINGBAT
|
|
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|
|
WRAP
|
|
The WRAP attribute is used for multicolumn lists. Use wrap=vert if you want to arrange the list items down the page before wrapping to the next column. Use wrap=horiz if you want to arrange the items across the page (less useful). The user agent is
responsible for determining how many columns are appropriate.
|
|
|
COMPACT
|
|
The presence of this attribute indicates the User agent should use reduced interitem spacing. In practice, there are several ways to increase the compactness of lists: reduced vertical interitem spacing, smaller font size, or even to avoid line breaks
between items. This is best handled through associated style sheets and the class attribute.
|
|
OL (ordered list) <OL> </OL>
|
|
II
|
An ordered list typically is a numbered list of items. HTML 3.0 gives you the ability to control the sequence number—to continue where the previous list left off, or to start at a particular number. The numbering style is left to associated style
sheets, such as whether nested lists contribute to a compound item number; for example, "3.1.5", or whether numbers are rendered as arabic, upper- or lowercase roman numerals or using the numbering scheme appropriate to the language context.
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|
|
The opening list tag must be <OL>. It is followed by an optional list header (<LH>caption</LH>) and then by the first list item (<LI>). For example:
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|
<OL>
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|
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|
|
<LH>Meeting Agenda</LH>
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|
<LI>Minutes of the last meeting
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|
<LI>Do we need yet more meetings?
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|
<LI>Any other business
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|
</OL>
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ID
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LANG
|
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CLASS
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|
CLEAR
|
|
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|
|
CONTINUE
|
|
Don't restart the sequence number, or continue where previous list left off (for example, <OL CONTINUE>)
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|
|
SEQNUM
|
|
|
|
|
COMPACT
|
|
|
|
DL - (Definition Lists)<DL></DL>
|
|
II
|
A definition list is a list of terms and corresponding definitions. Definition lists are typically formatted with the term on the left with the definition following on the right or on the next line. The definition text is typically indented with respect
to the term.
|
|
|
|
|
An alternative format places the term left aligned in a wide margin and the definition on one or more lines to the right of the term. If the DT term does not fit in the DT column (one third of the display area), it may be extended across the page with
the DD section moved to the next line or wrapped onto successive lines of the left column.
|
|
|
|
|
The opening list tag must be <DL>. It is followed by an optional list header (<LH>caption</LH>) and then by term names (<DT>) and definitions (<DD>). For example:
|
|
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|
|
<DL>
|
|
|
|
|
<LH>List Header</LH>
|
|
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|
|
<DT>Term 1<dd> This is the definition of the first term.
|
|
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|
|
<DT>Term 2<dd> This is the definition of the second term.
|
|
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|
|
</DL>
|
|
|
ID
|
|
|
|
|
LANG
|
|
|
|
|
CLASS
|
|
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|
|
CLEAR
|
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|
COMPACT
|
|
|
|
Figures <FIG> </FIG>
|
|
II
|
The FIG element is used for figures.
|
|
|
|
|
Subsequent elements will be flowed around the figure if there is sufficient room. This behaviour is disabled when the align attribute is center (the default) or justify.
|
|
|
|
|
Figure overlays provide for more effective use of caching as small changes to a figure in a subsequent document incur only the penalty of downloading the overlays and not the larger base figure, as the latter is already in the cache. The figure
description text is intended to convey the content of the figure for people with non-graphical user agents, while the figure caption and credit are rendered on both graphical and non-graphical user agents. The FIG element improves on the IMG element by
allowing authors to use markup for the description text. The content model allows authors to include headers, which is appropriate when the headers are part of the image data. It also allows graphical hypertext links to be specified in the markup and
interpreted by the user agent rather than the server. The anchor elements in the figure description text play a dual role: Non-graphical user agents show conventional hypertext links, while for graphical user agents, the same anchor elements specify
graphical hypertext links, with the SHAPE attribute designating the hotzones. This is designed to simplify the task of authors writing for both audiences. Hopefully, the FIG element will help to combat the tendency for authors to forget about people
limited to terminal access or the visually impaired relying on text to speech, as the new element forces you to write description text to define the graphical hypertext links. For some applications the hotzones are dynamically defined by programs running
on the server. HTML 3.0 allows clicks and drags to be passed to the server with the IMAGEMAP attribute. Hotzones may also be specified as part of the graphics data format e.g. as in VRML. Hotzones in the FIG element take precedence over hotzones in the
graphics data, which in turn take precedence over passing events to a server imagemap program. Hotzones in overlay graphics data take precedence over hotzones in figure data. Similarly, the imagemap attribute in overlays takes precedence over the imagemap
attribute for the figure. For a group of overlapping overlays the precedence is determined by the order the OVERLAY elements appear within the FIG element. Later overlays take precedence over earlier ones. Examples:
|
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|
|
Photographic image with caption and credits:
|
|
|
|
|
<FIG SRC="nicodamus.jpeg">
|
|
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|
|
<CAPTION>Ground dweller: <I>Nicodamus bicolor</I>
|
|
|
|
|
builds silk snares</CAPTION>
|
|
|
|
|
<P>A small hairy spider light fleshy red in color with a brown abdomen.
|
|
|
|
|
<CREDIT>J. A. L. Cooke/OSF</CREDIT>
|
|
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|
|
</FIG>
|
|
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ID
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|
LANG
|
|
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|
|
CLASS
|
|
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|
|
CLEAR
|
|
|
|
|
NOFLOW
|
|
The presence of this attribute disables text flow around the figure. It avoids the need to use the CLEAR or NEEDS attributes on the following element.
|
|
|
SRC
|
|
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|
MD
|
|
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|
|
ALIGN
|
|
Specifies horizontal alignment of the figure:
|
|
|
|
|
BLEEDLEFT Flush left with the left (window) border.
|
|
|
|
|
LEFT Flush left with the left text margin.
|
|
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|
|
CENTER The figure is centered between the text margins and text flow around the figure is disabled. This is the default setting for ALIGN.
|
|
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|
|
RIGHT Flush right with the right text margin.
|
|
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|
|
BLEEDRIGHT Flush right with the right (window) border
|
|
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|
|
JUSTIFY When applicable the figure should be magnified or reduced to fill the space between the left and right text margins. Text flow around the figure is disabled for align=justify.
|
|
|
WIDTH
|
|
|
|
|
HEIGHT
|
|
|
|
|
UNITS
|
|
|
|
|
IMAGEMAP
|
|
Specifies a URI for processing image clicks and drags.
|
Tables
|
|
|
|
|
Tables <TABLE> </TABLE>
|
|
III
|
The HTML table model has been chosen for its simplicity and flexibility. By default the table is automatically sized according to the cell contents and the current window size.
|
|
|
|
|
The COLSPEC attribute can be used when needed to exert control over column widths, either by setting explicit widths or by specifying relative widths. You can also specify the table width explicitly or as a fraction of the current margins (see WIDTH
attribute).
|
|
|
|
|
Table start with an optional caption followed one or more rows. Each row is formed by one or more cells, which are differentiated into header and data cells. Cells can be merged across rows and columns, and include attributes assisting rendering to
speech and braille, or for exporting table data into databases. The model provides little direct support for control over appearence, for example border styles and margins, as these can be handled via subclassing and associated style sheets.
|
|
|
|
|
Tables can contain a wide range of content, such as headers, lists, paragraphs, forms, figures, preformatted text and even nested tables. When the table is flush left or right, subsequent elements will be flowed around the table if there is sufficient
room. This behaviour is disabled when the noflow attribute is given or the table align attribute is center (the default), or justify. Example:
|
|
|
|
|
<TABLE BORDER>
|
|
|
|
|
<CAPTION>A test table with merged cells</CAPTION>
|
|
|
|
|
<TR><TH ROWSPAN=2><TH COLSPAN=2>Average
|
|
|
|
|
<TH ROWSPAN=2>other<BR>category<TH>Misc
|
|
|
|
|
<TR><TH>height<TH>weight
|
|
|
|
|
<TR><TH ALIGN=LEFT>males<TD>1.9<TD>0.003
|
|
|
|
|
<TR><TH ALIGN=LEFT ROWSPAN=2>females<TD>1.7<TD>0.002
|
|
|
|
|
</TABLE>
|
|
|
|
|
There are several points to note:
|
|
|
|
|
By default, header cells are centered while data cells are flush left. This can be overriden by the ALIGN attribute for the cell; the COLSPEC attribute for the TABLE element; or the ALIGN attribute on the enclosing row's TR element (from the most
specific to the least).
|
|
|
|
|
Cells may be empty.
|
|
|
|
|
Cells spanning rows contribute to the column count on each of the spanned rows, but only appear in the markup once (in the first row spanned).
|
|
|
|
|
If the column count for the table is greater than the number of cells for a given row (after including cells for spanned rows), the missing cells are treated as occurring on the right handside of the table, and rendered as empty cells.
|
|
|
|
|
The row count is determined by the TR elements - any rows implied by cells spanning rows beyond this should be ignored. The user agent should be able to recover from a missing <TR> tag prior to the first row as the TH and TC elements can only
occur within the TR element.
|
|
|
|
|
It is invalid to have cells overlap, see below for an example. In such cases, the rendering is implementation dependent.
|
|
|
BORDER
|
|
Adds borders to separate rows and columns in tables.
|
|
Table Row <TR> </TR>
|
|
III
|
Marks the begining and end of table rows.
|
|
Table Data <TD> </TD>
|
|
III
|
Enclosed the table data.
|
|
|
COLSPAN
|
|
Modifies the number of columns a cell will span.
|
|
|
ROWSPAN
|
|
Modifies the number of columns a row will span.
|
|
|
ALIGN
|
|
|
|
|
NOWRAP
|
|
|
|
Table Heading <TH> </TH>
|
|
III
|
Encloses table heading.
|
|
|
COLSPAN
|
|
|
|
|
ROWSPAN
|
|
|
|
|
ALIGN
|
|
|
|
|
NOWRAP
|
|
|
|
Captions <CAPTION> </CAPTION>
|
|
III
|
Creates a table title outsidethe table.
|
|
|
ID
|
|
|
|
|
LANG
|
|
|
|
|
CLASS
|
|
|
|
|
CLEAR
|
|
|
|
|
NOFLOW
|
|
|
|
|
ALIGN
|
|
|
|
|
UNITS
|
|
|
|
|
COLSPEC
|
|
The colspec attribute is a list of column widths and alignment specifications. The columns are listed from left to right with a capital letter followed by a number, e.g. COLSPEC="L20 C8 L40". The letter is L for left, C for center, R for right
alignment of cell contents. J is for justification, when feasible, otherwise this is treated in the same way as L for left alignment. D is for decimal alignment, see DP attribute.
|
|
|
|
|
The number specifies the width in en's, pixels or as a fractional value of the table width, as according to the associated units attribute. This approach is more compact than used with most SGML table models and chosen to simplify hand entry. The width
attribute allows you to specify the width of the table in pixels, em units or as a percentage of the space between the current left and right margins.
|
|
|
DP
|
|
|
|
|
WIDTH
|
|
|
|
|
BORDER
|
|
This presence of this attribute instructs the user agent to render borders around tables. For instance: <TABLE BORDER>. The precise appearence, along with the size of margins around cells, can be controlled by associated style sheets, or via
information in the STYLE element in the document head. Subclassing tables, rows and cells is particularly useful in this regard.
|
|
|
NOWRAP
|
|
|
Math
|
|
|
|
|
HTML Math <MATH> </MATH>
|
|
III
|
The <MATH> element is used to include math expressions in the current line. HTML math is powerful enough to describe the range of math expressions you can create in common word processing packages, as well as being suitable for rendering to
speech. When rendering to fixed pitch text-only media, simple text graphics can be used for math symbols such as the integration sign, while other symbols can be rendered using their entity names. The SGML SHORTREF capability is used to provide
abbreviations for hidden brackets, subscripts and superscripts.
|
|
|
|
|
Example:
|
|
|
|
|
- the integral from a to b of f(x) over 1+x
|
|
|
|
|
<MATH>∫_a_^b^{f(x)<over>1+x} dx</MATH>
|
|
|
|
|
which can be rendered on afixed pitch text-only medium as:
|
|
|
|
|
b
|
|
|
|
|
/ f(x)
|
|
|
|
|
| ------- dx
|
|
|
|
|
/ 1 + x
|
|
|
|
|
a
|
|
BOX <BOX> </BOX>
|
|
III
|
Used for hidden brackets, stretchy delimiters, and placing one expression over another (e.g. numerators and denominators).
|
|
SUB, SUP <SUB> </SUB> <SUP> </SUP>
|
|
III
|
Subscripts and superscripts Also used for limits.
|
|
ABOVE <ABOVE> </ABOVE>
|
|
III
|
Used to draw an arrow, line or symbol above an expression.
|
|
BELOW <BELOW> </BELOW>
|
|
III
|
Used to draw an arrow, line or symbol below an expression.
|
|
VEC, BAR, DOT, DDOT, HAT, TILDE <VEC></VEC> <BAR></BAR> <DOT></DOT> <DDOT> </DDOT> <HAT></HAT> <TILDE> </TILDE>
|
|
III
|
These are convenience tags for common accents as an alternative to using ABOVE.
|
|
SQRT, ROOT <SQRT> </SQRT> <ROOT> </ROOT>
|
|
III
|
For square roots and other roots of an expression.
|
|
ARRAY <ARRAY><ARRAY>
|
|
III
|
For matrices and other kinds of arrays.
|
|
TEXT <TEXT> </TEXT>
|
|
III
|
Used to include a short piece of text within a math element, and often combined with SUB or SUP elements.
|
|
B, T, BT <B></B> <T></T> <BT></BT>
|
|
III
|
These elements are used override the default rendering. B renders the enclosed expression in an bold face. T designates a term to be rendered in an upright font, while BT designates a term to be rendered in a bold upright font. The class attribute can
be used to describe the kind of term, e.g. vector, tensor, or matrix.
|
|
|
ID
|
|
|
|
|
CLASS
|
|
|
|
|
BOX
|
|
The presence of this attribute causes the user agent to draw a rectangular box around the formulae.
|
|
Horizontal Rules <HR>
|
|
II
|
The <HR> element is used for horizontal rules that act as dividers between sections. The SRC attribute can be used to designate a custom graphic, otherwise subclass HR with the CLASS attribute and specify the appropriate rendering with an
associated style sheet.
|
|
|
ID
|
|
|
|
|
CLASS
|
|
|
|
|
CLEAR
|
|
|
|
|
SRC
|
|
|
|
|
MD
|
|
|
Preformatted Text, etc.
|
|
|
|
|
Preformatted Text (PRE) <PRE> </PRE>
|
|
|
Preformatted text between the start and end PRE tag is rendered using a fixed with font, in addition whitespace characters are treated literally. The spacing and line breaks are rendered directly, unlike other elements, for which repeated whitespace
chararacters are collapsed to a single space character and line breaks introduced automatically.
|
|
|
ID
|
|
|
|
|
LANG
|
|
|
|
|
CLASS
|
|
|
|
|
CLEAR
|
|
|
|
|
WIDTH
|
|
|
|
Admonishments <NOTE> </NOTE>
|
|
III
|
The NOTE element is designed for use as admonishments such as notes, cautions or warnings, as commonly used in technical documentation. The CLASS attribute specifies the type of the element and is typically associated with different graphics such as a
road traffic warning sign. The graphic can be customized with the SRC attribute. Example:
|
|
|
|
|
<NOTE CLASS=WARNING>Please check with the local weather service before starting your climb. The mountain weather is subject to rapid deterioration. It is essential to carry a good map and compass.</NOTE>
|
|
|
|
|
The class names: NOTE, CAUTION and WARNING are recommended for standard admonishments. In the absence of the CLASS attribute, a NOTE element is typically rendered indented, without an accompanying graphic.
|
|
|
ID
|
|
|
|
|
LANG
|
|
|
|
|
CLASS
|
|
|
|
|
CLEAR
|
|
|
|
|
SRC
|
|
|
|
|
MD
|
|
|
|
Footnotes <FN> </FN>
|
|
III
|
The FN element is designed for footnotes, and when practical, rendered as pop-up notes.
|
|
|
|
|
Example:
|
|
|
|
|
<DL>
|
|
|
|
|
<DT>Hamlet: <DD>You should not have believed me, for virtue cannot so <a href="#fn1">inoculate</a> our old stock but we shall <a
|
|
|
|
|
href="#fn2">relish of it</a>. I loved you not.
|
|
|
|
|
<DT>Ophelia: <DD> I was the more deceived.
|
|
|
|
|
<DT>Hamlet: <DD>Get thee to a nunnery. Why wouldst thou be a breeder of sinners? I am myself <a href="#fn2">indifferent honest</a>
|
|
|
|
|
...
|
|
|
|
|
</DL>
|
|
|
|
|
<fn id=fn1><i>inoculate</i> - graft</fn>
|
|
|
|
|
<fn id=fn2><i>relish of it</i> - smack of it (our old sinful nature)</fn>
|
|
|
|
|
<fn id=fn3><i>indifferent honest</i> - moderately virtuous</fn>
|
|
|
ID
|
|
|
|
|
LANG
|
|
|
|
|
CLASS
|
|
|
|
Block Quotes <BQ> </BQ>
|
|
III
|
The BQ element is used for extended quotations. The tag name has been abbreviated from HTML 2.0's BLOCKQUOTE to the more convenient BQ, and the content model extended to allow the source of the quotation to be credited.
|
|
|
ID
|
|
|
|
|
LANG
|
|
|
|
|
CLASS
|
|
|
|
|
CLEAR
|
|
|
|
|
NOWRAP
|
|
|
|
ADDRESS <ADDRESS> </ADDRESS>
|
|
II
|
The ADDRESS element specifies such information as address, signature and authorship for the current document, and typically placed at the top or bottom of the document. When used with %text, the element acts similar to a paragraph with breaks before and
after.
|
|
|
ID
|
|
|
|
|
LANG
|
|
|
|
|
CLASS
|
|
|
|
|
CLEAR
|
|
|
|
|
NOWRAP
|
|
|
Forms
|
|
|
|
|
FORM <FORM ....> </FORM>
|
|
II
|
HTML fill-out forms can be used for questionaires, hotel reservations, order forms, data entry and a wide variety of other applications. The form is specified as part of an HTML document. The user fills in the form and then submits it. The user agent
then sends the form's contents as designated by the FORM element. Typically, this is to an HTTP server, but you can also email form contents for asynchronous processing.
|
|
|
|
|
Forms are created by placing input fields within paragraphs, preformatted text, lists and tables. This gives considerable flexibility in designing the layout of forms.
|
|
|
|
|
HTML 3.0 supports the following kinds of fields:
|
|
|
|
|
W Simple text fields
|
|
|
|
|
W Multi-line text fields
|
|
|
|
|
W Radio buttons
|
|
|
|
|
W Checkboxes
|
|
|
|
|
W Range controls (sliders, or knobs)
|
|
|
|
|
W Single/multiple choice menus
|
|
|
|
|
W Scribble on image
|
|
|
|
|
W File widgets for attaching files to forms.
|
|
|
|
|
W Submit buttons for sending form contents
|
|
|
|
|
W Reset buttons for resetting fields to their initial values
|
|
|
|
|
W Hidden fields for book keeping information
|
|
|
ACTION
|
|
The ACTION attribute is a URL specifying the location to which the contents of the form is submitted to elicit a response. If the ACTION is missing, the URL for the document itself is assumed. The way data is submitted varies with the access protocol of
the URL, and with the values of the METHOD and ENCTYPE attributes.
|
|
|
METHOD
|
|
This specifies variations in the protocol used to send the form contents. It is currently restricted to GET (the default) or POST. The attribute was introduced to inform user agents which HTTP methods the server supports.
|
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ENCTYPE
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This attribute specifies the MIME content type to be used to encode the form contents. It defaults to the string: "application/x-www-form-urlencoded"
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SCRIPT
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This can be used to give a URI for a script. The scripting language and the interface with the user agent is not part of the HTML 3.0 specification. |
