How to Get Online 1996 Spring/HOW2GON.ISO/mac/Servers & CGI/CmmCGI/Documentation/HTML2_0.DOC Part 2

Text File | 1996-02-06 | 19.4 KB | 580 lines | [ttro/ttxt]

5.7. Phrase Markup

   Phrases may be marked up according to idiomatic usage, typographic
   appearance, or for use as hyperlink anchors.

   User agents must render highlighted phrases distinctly from plain
   text. Additionally, <EM> content must be rendered as distinct from
   <STRONG> content, and <B> content must rendered as distinct from <I>
   content.

   Phrase elements may be nested within the content of other phrase
   elements; however, HTML user agents may render nested phrase elements

   indistinctly from non-nested elements:

   plain <B>bold <I>italic</I></B> may be rendered
   the same as plain <B>bold </B><I>italic</I>

5.7.1. Idiomatic Elements

   Phrases may be marked up to indicate certain idioms.

      NOTE - User agents may support the <DFN> element, not included in
      this specification, as it has been deployed to some extent. It is
      used to indicate the defining instance of a term, and it is
      typically rendered in italic or bold italic.

5.7.1.1. Citation: CITE

      The <CITE> element is used to indicate the title of a book or
      other citation. It is typically rendered as italics. For example:

      He just couldn't get enough of <cite>The Grapes of Wrath</cite>.

5.7.1.2. Code: CODE

      The <CODE> element indicates an example of code, typically
      rendered in a mono-spaced font. The <CODE> element is intended for
      short words or phrases of code; the <PRE> block structuring
      element (5.5.2, "Preformatted Text: PRE") is more appropriate
       for multiple-line listings. For example:

      The expression <code>x += 1</code>
      is short for <code>x = x + 1</code>.

5.7.1.3. Emphasis: EM

      The <EM> element indicates an emphasized phrase, typically
      rendered as italics. For example:

      A singular subject <em>always</em> takes a singular verb.

5.7.1.4. Keyboard: KBD

      The <KBD> element indicates text typed by a user, typically
      rendered in a mono-spaced font. This is commonly used in
      instruction manuals. For example:

      Enter <kbd>FIND IT</kbd> to search the database.

5.7.1.5. Sample: SAMP

      The <SAMP> element indicates a sequence of literal characters,
      typically rendered in a mono-spaced font. For example:

      The only word containing the letters <samp>mt</samp> is dreamt.

5.7.1.6. Strong Emphasis: STRONG

      The <STRONG> element indicates strong emphasis, typically rendered
      in bold. For example:

      <strong>STOP</strong>, or I'll say "<strong>STOP</strong>" again!

5.7.1.7. Variable: VAR

      The <VAR> element indicates a placeholder variable, typically
      rendered as italic. For example:

      Type <SAMP>html-check <VAR>file</VAR> | more</SAMP>
      to check <VAR>file</VAR> for markup errors.

5.7.2. Typographic Elements

      Typographic elements are used to specify the format of marked
      text.

      Typical renderings for idiomatic elements may vary between user
      agents. If a specific rendering is necessary -- for example, when
      referring to a specific text attribute as in "The italic parts are
      mandatory" -- a typographic element can be used to ensure that the
      intended typography is used where possible.

      NOTE - User agents may support some typographic elements not
      included in this specification, as they have been deployed to some
      extent. The <STRIKE> element indicates horizontal line through the
      characters, and the <U> element indicates an underline.

5.7.2.1. Bold: B

   The <B> element indicates bold text. Where bold typography is
   unavailable, an alternative representation may be used.

5.7.2.2. Italic: I

   The <I> element indicates italic text. Where italic typography is
   unavailable, an alternative representation may be used.


5.7.2.3. Teletype: TT

   The <TT> element indicates teletype (monospaced )text. Where a
   teletype font is unavailable, an alternative representation may be
   used.

5.7.3. Anchor: A

   The <A> element indicates a hyperlink anchor (see 7, "Hyperlinks").
   At least one of the NAME and HREF attributes should be present.
   Attributes of the <A> element:

    HREF
            gives the URI of the head anchor of a hyperlink.

    NAME
            gives the name of the anchor, and makes it available as
            a head of a hyperlink.

    TITLE
            suggests a title for the destination resource --
            advisory only. The TITLE attribute may be used:

                * for display prior to accessing the destination
                resource, for example, as a margin note or on a
                small box while the mouse is over the anchor, or
                while the document is being loaded;

                * for resources that do not include a title, such as
                graphics, plain text and Gopher menus, for use as a
                window title.

    REL
            The REL attribute gives the relationship(s) described by
            the hyperlink. The value is a whitespace separated list
            of relationship names. The semantics of link
            relationships are not specified in this document.

    REV
            same as the REL attribute, but the semantics of the
            relationship are in the reverse direction. A link from A
            to B with REL="X" expresses the same relationship as a
            link from B to A with REV="X". An anchor may have both
            REL and REV attributes.

    URN
            specifies a preferred, more persistent identifier for
            the head anchor of the hyperlink. The syntax and

            semantics of the URN attribute are not yet specified.

    METHODS
            specifies methods to be used in accessing the
            destination, as a whitespace-separated list of names.
            The set of applicable names is a function of the scheme
            of the URI in the HREF attribute. For similar reasons as
            for the TITLE attribute, it may be useful to include the
            information in advance in the link. For example, the
            HTML user agent may chose a different rendering as a
            function of the methods allowed; for example, something
            that is searchable may get a different icon.

5.8. Line Break: BR

   The <BR> element specifies a line break between words (see 6,
   "Characters, Words, and Paragraphs"). For example:

    <P> Pease porridge hot<BR>
    Pease porridge cold<BR>
    Pease porridge in the pot<BR>
    Nine days old.

5.9. Horizontal Rule: HR

   The <HR> element is a divider between sections of text; typically a
   full width horizontal rule or equivalent graphic.  For example:

    <HR>
    <ADDRESS>February 8, 1995, CERN</ADDRESS>
    </BODY>

5.10. Image: IMG

   The <IMG> element refers to an image or icon via a hyperlink (see
   7.3, "Simultaneous Presentation of Image Resources").

   HTML user agents may process the value of the ALT attribute as an
   alternative to processing the image resource indicated by the SRC
   attribute.

      NOTE - Some HTML user agents can process graphics linked via
      anchors, but not <IMG> graphics. If a graphic is essential, it
      should be referenced from an <A> element rather than an <IMG>
      element. If the graphic is not essential, then the <IMG> element
      is appropriate.

   Attributes of the <IMG> element:

    ALIGN
            alignment of the image with respect to the text
            baseline.

                * `TOP' specifies that the top of the image aligns
                with the tallest item on the line containing the
                image.

                * `MIDDLE' specifies that the center of the image
                aligns with the baseline of the line containing the
                image.

                * `BOTTOM' specifies that the bottom of the image
                aligns with the baseline of the line containing the
                image.

    ALT
            text to use in place of the referenced image resource,
            for example due to processing constraints or user
            preference.

    ISMAP
            indicates an image map (see 7.6, "Image Maps").

    SRC
            specifies the URI of the image resource.

                NOTE - In practice, the media types of image
                resources are limited to a few raster graphic
                formats: typically `image/gif', `image/jpeg'. In
                particular, `text/html' resources are not
                intended to be used as image resources.

    Examples of use:

    <IMG SRC="triangle.xbm" ALT="Warning:"> Be sure
    to read these instructions.

    <a href="http://machine/htbin/imagemap/sample">
    <IMG SRC="sample.xbm" ISMAP>
    </a>

7. Hyperlinks

   In addition to general purpose elements such as paragraphs and lists,
   HTML documents can express hyperlinks. An HTML user agent allows the
   user to navigate these hyperlinks.


   A hyperlink is a relationship between two anchors, called the head
   and the tail of the hyperlink[DEXTER]. Anchors are identified by an
   anchor address: an absolute Uniform Resource Identifier (URI),
   optionally followed by a '#' and a sequence of characters called a
   fragment identifier. For example:

   http://www.w3.org/hypertext/WWW/TheProject.html
   http://www.w3.org/hypertext/WWW/TheProject.html#z31

   In an anchor address, the URI refers to a resource; it may be used in
   a variety of information retrieval protocols to obtain an entity that
   represents the resource, such as an HTML document. The fragment
   identifier, if present, refers to some view on, or portion of the
   resource.

   Each of the following markup constructs indicates the tail anchor of
   a hyperlink or set of hyperlinks:

        * <A> elements with HREF present.

        * <LINK> elements.

        * <IMG> elements.

        * <INPUT> elements with the SRC attribute present.

        * <ISINDEX> elements.

        * <FORM> elements with `METHOD=GET'.

   These markup constructs refer to head anchors by a URI, either
   absolute or relative, or a fragment identifier, or both.

   In the case of a relative URI, the absolute URI in the address of the
   head anchor is the result of combining the relative URI with a base
   absolute URI as in [RELURL]. The base document is taken from the
   document's <BASE> element, if present; else, it is determined as in
   [RELURL].

8. Forms

   A form is a template for a form data set and an associated
   method and action URI. A form data set is a sequence of
   name/value pair fields. The names are specified on the NAME
   attributes of form input elements, and the values are given
   initial values by various forms of markup and edited by the
   user. The resulting form data set is used to access an
   information service as a function of the action and method.

   Forms elements can be mixed in with document structuring
   elements. For example, a <PRE> element may contain a <FORM>
   element, or a <FORM> element may contain lists which contain
   <INPUT> elements. This gives considerable flexibility in
   designing the layout of forms.

   Form processing is a level 2 feature.

8.1. Form Elements

8.1.1. Form: FORM

   The <FORM> element contains a sequence of input elements, along
   with document structuring elements. The attributes are:

    ACTION
            specifies the action URI for the form. The action URI of
            a form defaults to the base URI of the document (see 7,
            "Hyperlinks").

    METHOD
            selects a method of accessing the action URI. The set of
            applicable methods is a function of the scheme of the
            action URI of the form. See 8.2.2, "Query Forms:
            METHOD=GET" and 8.2.3, "Forms with Side-Effects:
            METHOD=POST".

    ENCTYPE
            specifies the media type used to encode the name/value
            pairs for transport, in case the protocol does not
            itself impose a format. See 8.2.1, "The form-urlencoded
            Media Type".

8.1.2. Input Field: INPUT

   The <INPUT> element represents a field for user input. The TYPE
   attribute discriminates between several variations of fields.


   The <INPUT> element has a number of attributes. The set of applicable
   attributes depends on the value of the TYPE attribute.

8.1.2.1. Text Field: INPUT TYPE=TEXT

   The default value of the TYPE attribute is `TEXT', indicating a
   single line text entry field. (Use the <TEXTAREA> element for multi-
   line text fields.)

   Required attributes are:

    NAME
            name for the form field corresponding to this element.

    The optional attributes are:

    MAXLENGTH
            constrains the number of characters that can be entered
            into a text input field. If the value of MAXLENGTH is
            greater the the value of the SIZE attribute, the field
            should scroll appropriately. The default number of
            characters is unlimited.

    SIZE
            specifies the amount of display space allocated to this
            input field according to its type. The default depends
            on the user agent.

    VALUE
            The initial value of the field.

    For example:

<p>Street Address: <input name=street><br>
Postal City code: <input name=city size=16 maxlength=16><br>
Zip Code: <input name=zip size=10 maxlength=10 value="99999-9999"><br>

8.1.2.2. Password Field: INPUT TYPE=PASSWORD

   An <INPUT> element with `TYPE=PASSWORD' is a text field as above,
   except that the value is obscured as it is entered. (see also: 10,
   "Security Considerations").

   For example:

<p>Name: <input name=login> Password: <input type=password name=passwd>



8.1.2.3. Check Box: INPUT TYPE=CHECKBOX

   An <INPUT> element with `TYPE=CHECKBOX' represents a boolean choice.
   A set of such elements with the same name represents an n-of-many
   choice field. Required attributes are:

    NAME
            symbolic name for the form field corresponding to this
            element or group of elements.

    VALUE
            The portion of the value of the field contributed by
            this element.

    Optional attributes are:

    CHECKED
            indicates that the initial state is on.

    For example:

  <p>What flavors do you like?
  <input type=checkbox name=flavor value=vanilla>Vanilla<br>
  <input type=checkbox name=flavor value=strawberry>Strawberry<br>
  <input type=checkbox name=flavor value=chocolate checked>Chocolate<br>

8.1.2.4. Radio Button: INPUT TYPE=RADIO

   An <INPUT> element with `TYPE=RADIO' represents a boolean choice. A
   set of such elements with the same name represents a 1-of-many choice
   field. The NAME and VALUE attributes are required as for check boxes.
   Optional attributes are:

    CHECKED
            indicates that the initial state is on.
   At all times, exactly one of the radio buttons in a set is checked.
   If none of the <INPUT> elements of a set of radio buttons specifies
   `CHECKED', then the user agent must check the first radio button of
   the set initially.

   For example:

    <p>Which is your favorite?
    <input type=radio name=flavor value=vanilla>Vanilla<br>
    <input type=radio name=flavor value=strawberry>Strawberry<br>
    <input type=radio name=flavor value=chocolate>Chocolate<br>



8.1.2.5. Image Pixel: INPUT TYPE=IMAGE

   An <INPUT> element with `TYPE=IMAGE' specifies an image resource to
   display, and allows input of two form fields: the x and y coordinate
   of a pixel chosen from the image. The names of the fields are the
   name of the field with `.x' and `.y' appended.  `TYPE=IMAGE' implies
   `TYPE=SUBMIT' processing; that is, when a pixel is chosen, the form
   as a whole is submitted.

   The NAME attribute is required as for other input fields. The SRC
   attribute is required and the ALIGN is optional as for the <IMG>
   element (see 5.10, "Image: IMG").

   For example:

    <p>Choose a point on the map:
    <input type=image name=point src="map.gif">

8.1.2.6. Hidden Field: INPUT TYPE=HIDDEN

   An <INPUT> element with `TYPE=HIDDEN' represents a hidden field.The
   user does not interact with this field; instead, the VALUE attribute
   specifies the value of the field. The NAME and VALUE attributes are
   required.

   For example:

   <input type=hidden name=context value="l2k3j4l2k3j4l2k3j4lk23">

8.1.2.7. Submit Button: INPUT TYPE=SUBMIT

   An <INPUT> element with `TYPE=SUBMIT' represents an input option,
   typically a button, that instructs the user agent to submit the form.
   Optional attributes are:

    NAME
            indicates that this element contributes a form field
            whose value is given by the VALUE attribute. If the NAME
            attribute is not present, this element does not
            contribute a form field.

    VALUE
            indicates a label for the input (button).

    You may submit this request internally:
    <input type=submit name=recipient value=internal><br>
    or to the external world:
    <input type=submit name=recipient value=world>

8.1.2.8. Reset Button: INPUT TYPE=RESET

   An <INPUT> element with `TYPE=RESET' represents an input option,
   typically a button, that instructs the user agent to reset the form's
   fields to their initial states. The VALUE attribute, if present,
   indicates a label for the input (button).

   When you are finished, you may submit this request:
   <input type=submit><br>
   You may clear the form and start over at any time: <input type=reset>

8.1.3. Selection: SELECT

   The <SELECT> element constrains the form field to an enumerated list
   of values. The values are given in <OPTION> elements.  Attributes
   are:

    MULTIPLE
            indicates that more than one option may be included in
            the value.

    NAME
            specifies the name of the form field.

    SIZE
            specifies the number of visible items. Select fields of
            size one are typically pop-down menus, whereas select
            fields with size greater than one are typically lists.

    For example:

    <SELECT NAME="flavor">
    <OPTION>Vanilla
    <OPTION>Strawberry
    <OPTION value="RumRasin">Rum and Raisin
    <OPTION selected>Peach and Orange
    </SELECT>

   The initial state has the first option selected, unless a SELECTED
   attribute is present on any of the <OPTION> elements.

8.1.3.1. Option: OPTION

   The Option element can only occur within a Select element. It
   represents one choice, and has the following attributes:

    SELECTED
            Indicates that this option is initially selected.

    VALUE
            indicates the value to be returned if this option is
            chosen. The field value defaults to the content of the
            <OPTION> element.

   The content of the <OPTION> element is presented to the user to
   represent the option. It is used as a returned value if the VALUE
   attribute is not present.

8.1.4. Text Area: TEXTAREA

   The <TEXTAREA> element represents a multi-line text field.
   Attributes are:

    COLS
            the number of visible columns to display for the text
            area, in characters.

    NAME
            Specifies the name of the form field.

    ROWS
            The number of visible rows to display for the text area,
            in characters.

    For example:

    <TEXTAREA NAME="address" ROWS=6 COLS=64>
    HaL Computer Systems
    1315 Dell Avenue
    Campbell, California 95008
    </TEXTAREA>

   The content of the <TEXTAREA> element is the field's initial value.

   Typically, the ROWS and COLS attributes determine the visible
   dimension of the field in characters. The field is typically rendered
   in a fixed-width font. HTML user agents should allow text to extend
   beyond these limits by scrolling as needed.