This is Info file ../info/w3.info, produced by Makeinfo version 1.68 from the input file w3.texi. INFO-DIR-SECTION World Wide Web INFO-DIR-SECTION GNU Emacs Lisp START-INFO-DIR-ENTRY * Emacs/W3: (w3). Emacs/W3 World Wide Web browser. END-INFO-DIR-ENTRY This file documents the Emacs/W3 World Wide Web browser. Copyright (C) 1993, 1994, 1995, 1996 William M. Perry Copyright (C) 1996, 1997 Free Software Foundation Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies.  File: w3.info, Node: font-variant, Next: font-weight, Prev: font-style, Up: Font Properties font-variant ............ Value: normal | small-caps Initial: normal Applies to: all elements Inherited: yes Percentage N/A values: Another type of variation within a font family is the small-caps. In a small-caps font the lower case letters look similar to the uppercase ones, but in a smaller size and with slightly different proportions. The 'font-variant' property selects that font. A value of 'normal' selects a font that is not a small-caps font, 'small-caps' selects a small-caps font. It is acceptable (but not required) in CSS1 if the small-caps font is a created by taking a normal font and replacing the lower case letters by scaled uppercase characters. As a last resort, uppercase letters will be used as replacement for a small-caps font. The following example results in an 'H3' element in small-caps, with emphasized words in oblique small-caps: H3 { font-variant: small-caps } EM { font-style: oblique } There may be other variants in the font family as well, such as fonts with old-style numerals, small-caps numerals, condensed or expanded letters, etc. CSS1 has no properties that select those.  File: w3.info, Node: font-weight, Next: font-size, Prev: font-variant, Up: Font Properties font-weight ........... Supported normal | bold | 100 | 200 | 300 | 400 | 500 | 600 | 700 | Values: 800 | 900 Unsupported bolder | lighter Values: Initial: normal Applies to: all elements Inherited: yes Percentage N/A values: The 'font-weight' property selects the weight of the font. The values '100' to '900' form an ordered sequence, where each number indicates a weight that is at least as dark as its predecessor. The keyword 'normal' is synonymous with '400', and 'bold' is synonymous with '700'. Keywords other than 'normal' and 'bold' have been shown to be often confused with font names and a numerical scale was therefore chosen for the 9-value list. P { font-weight: normal } /* 400 */ H1 { font-weight: 700 } /* bold */ The 'bolder' and 'lighter' values select font weights that are relative to the weight inherited from the parent: STRONG { font-weight: bolder } There is no guarantee that there will be a darker face for each of the 'font-weight' values; for example, some fonts may have only a normal and a bold face, others may have eight different face weights. There is no guarantee on how a UA will map font faces within a family to weight values. The only guarantee is that a face of a given value will be no less dark than the faces of lighter values.  File: w3.info, Node: font-size, Next: font, Prev: font-weight, Up: Font Properties font-size ......... Supported | Values: Unsupported | Values: Initial: medium Applies to: all elements Inherited: yes Percentage relative to parent element's font size values: An keyword is an index to a table of font sizes computed and kept by the UA. Possible values are: * xx-small * x-small * small * medium * large * x-large * xx-large On a computer screen a scaling factor of 1.5 is suggested between adjacent indexes; if the 'medium' font is 10pt, the 'large' font could be 15pt. Different media may need different scaling factors. Also, the UA should take the quality and availability of fonts into account when computing the table. The table may be different from one font family to another. A keyword is interpreted relative to the table of font sizes and the font size of the parent element. Possible values are larger or smaller. For example, if the parent element has a font size of 'medium', a value of 'larger' will make the font size of the current element be 'large'. If the parent element's size is not close to a table entry, the UA is free to interpolate between table entries or round off to the closest one. The UA may have to extrapolate table values if the numerical value goes beyond the keywords. Length and percentage values should not take the font size table into account when calculating the font size of the element. Negative values are not allowed. On all other properties, 'em' and 'ex' length values refer to the font size of the current element. On the 'font-size' property, these length units refer to the font size of the parent element. Note that an application may reinterpret an explicit size, depending on the context. E.g., inside a VR scene a font may get a different size because of perspective distortion. Examples: P { font-size: 12pt; } BLOCKQUOTE { font-size: larger } EM { font-size: 150% } EM { font-size: 1.5em } If the suggested scaling factor of 1.5 is used, the last three declarations are identical.  File: w3.info, Node: font, Prev: font-size, Up: Font Properties font .... Value: [ || || ]? [ / ]? Initial: not defined for shorthand properties Applies to: all elements Inherited: yes Percentage allowed on and values: The 'font' property is a shorthand property for setting 'font-style' 'font-variant' 'font-weight' 'font-size', 'line-height' and 'font-family' at the same place in the style sheet. The syntax of this property is based on a traditional typographical shorthand notation to set multiple properties related to fonts. For a definition of allowed and initial values, see the previously defined properties. Properties for which no values are given are set to their initial value. P { font: 12pt/14pt sans-serif } P { font: 80% sans-serif } P { font: x-large/110% "new century schoolbook", serif } P { font: bold italic large Palatino, serif } P { font: normal small-caps 120%/120% fantasy } In the second rule, the font size percentage value ('80%') refers to the font size of the parent element. In the third rule, the line height percentage refers to the font size of the element itself. In the first three rules above, the 'font-style', 'font-variant' and 'font-weight' are not explicitly mentioned, which means they are all three set to their initial value ('normal'). The fourth rule sets the 'font-weight' to 'bold', the 'font-style' to 'italic' and implicitly sets 'font-variant' to 'normal'. The fifth rule sets the 'font-variant' ('small-caps'), the 'font-size' (120% of the parent's font), the 'line-height' (120% times the font size) and the 'font-family' ('fantasy'). It follows that the keyword 'normal' applies to the two remaining properties: 'font-style' and 'font-weight'.  File: w3.info, Node: Colors and Backgrounds, Next: Text Properties, Prev: Font Properties, Up: Properties Colors and Backgrounds ---------------------- These properties describe the color (often called foreground color) and background of an element (i.e. the surface onto which the content is rendered). One can set a background color and/or a background image. The position of the image, if/how it is repeated, and whether it is fixed or scrolled relative to the canvas can also be set. The 'color' property inherits normally. The background properties do not inherit, but the parent element's background will shine through by default because of the initial 'transparent' value on 'background-color'. NOTE: Currently, Emacs/W3 can only show background images under XEmacs. Emacs 19 doesn't have the support in its display code yet. * Menu: * color:: Foreground colors. * background-color:: Background colors. * background-image:: Background images. * background-repeat:: Controlling repeating of background images. * background-attachment:: Where background images are drawn. * background-position:: Where background images are drawn. * background:: Shorthand for all background properties.  File: w3.info, Node: color, Next: background-color, Prev: Colors and Backgrounds, Up: Colors and Backgrounds color ..... Value: Initial: User specific Applies to: all elements Inherited: yes Percentage N/A values: This property describes the text color of an element (often referred to as the foreground color). There are different ways to specify red: EM { color: red } /* natural language */ EM { color: rgb(255,0,0) } /* RGB range 0-255 */ See *Note Color Units:: for a description of possible color values.  File: w3.info, Node: background-color, Next: background-image, Prev: color, Up: Colors and Backgrounds background-color ................ Value: | transparent Initial: transparent Applies to: all elements Inherited: no Percentage N/A values: This property sets the background color of an element. H1 { background-color: #F00 }  File: w3.info, Node: background-image, Next: background-repeat, Prev: background-color, Up: Colors and Backgrounds background-image ................ Value: | none Initial: none Applies to: all elements Inherited: no Percentage N/A values: This property sets the background image of an element. When setting a background image, one should also set a background color that will be used when the image is unavailable. When the image is available, it is overlaid on top of the background color. BODY { background-image: url(marble.png) } P { background-image: none }  File: w3.info, Node: background-repeat, Next: background-attachment, Prev: background-image, Up: Colors and Backgrounds background-repeat ................. This property is not supported at all under Emacs/W3.  File: w3.info, Node: background-attachment, Next: background-position, Prev: background-repeat, Up: Colors and Backgrounds background-attachment ..................... This property is not supported at all under Emacs/W3.  File: w3.info, Node: background-position, Next: background, Prev: background-attachment, Up: Colors and Backgrounds background-position ................... This property is not supported at all under Emacs/W3.  File: w3.info, Node: background, Prev: background-position, Up: Colors and Backgrounds background .......... Value: || || || || Initial: not defined for shorthand properties Applies to: all elements Inherited: no Percentage allowed on values: The 'background' property is a shorthand property for setting the individual background properties (i.e., 'background-color', 'background-image', 'background-repeat', 'background-attachment' and 'background-position') at the same place in the style sheet. Possible values on the 'background' properties are the set of all possible values on the individual properties. BODY { background: red } P { background: url(chess.png) gray 50% repeat fixed } The 'background' property always sets all the individual background properties. In the first rule of the above example, only a value for 'background-color' has been given and the other individual properties are set to their initial value. In the second rule, all individual properties have been specified.  File: w3.info, Node: Text Properties, Next: Box Properties, Prev: Colors and Backgrounds, Up: Properties Text Properties --------------- * Menu: * word-spacing:: * letter-spacing:: * text-decoration:: * vertical-align:: * text-transform:: * text-align:: * text-indent:: * line-height::  File: w3.info, Node: word-spacing, Next: letter-spacing, Prev: Text Properties, Up: Text Properties word-spacing ............ Supported normal Values: Unsupported Values: Initial: normal Applies to: all elements Inherited: yes Percentage N/A values: The length unit indicates an addition to the default space between words. Values can be negative, but there may be implementation-specific limits. The UA is free to select the exact spacing algorithm. The word spacing may also be influenced by justification (which is a value of the 'align' property). H1 { word-spacing: 0.4em } Here, the word-spacing between each word in 'H1' elements would be increased by '1em'. NOTE: Emacs/W3 cannot currently support this, due to limitations in Emacs. It may be implemented in the future.  File: w3.info, Node: letter-spacing, Next: text-decoration, Prev: word-spacing, Up: Text Properties letter-spacing .............. Supported normal Values: Unsupported Values: Initial: normal Applies to: all elements Inherited: yes Percentage N/A values: The length unit indicates an addition to the default space between characters. Values can be negative, but there may be implementation-specific limits. The UA is free to select the exact spacing algorithm. The letter spacing may also be influenced by justification (which is a value of the 'align' property). BLOCKQUOTE { letter-spacing: 0.1em } Here, the letter-spacing between each character in 'BLOCKQUOTE' elements would be increased by '0.1em'. NOTE: Emacs/W3 cannot currently support this, due to limitations in Emacs. It may be implemented in the future.  File: w3.info, Node: text-decoration, Next: vertical-align, Prev: letter-spacing, Up: Text Properties text-decoration ............... Supported none | underline | line-through | blink Values: Unsupported overline Values: Initial: none Applies to: all elements Inherited: no, but see clarification below Percentage N/A values: This property describes decorations that are added to the text of an element. If the element has no text (e.g. the 'IMG' element in HTML) or is an empty element (e.g. ''), this property has no effect. A value of 'blink' causes the text to blink. The color(s) required for the text decoration should be derived from the 'color' property value. This property is not inherited, but elements should match their parent. E.g., if an element is underlined, the line should span the child elements. The color of the underlining will remain the same even if descendant elements have different 'color' values. A:link, A:visited, A:active { text-decoration: underline } The example above would underline the text of all links (i.e., all 'A' elements with a 'HREF' attribute). NOTE: The 'line-through' property is only supported under XEmacs currently. A patch has been sent to the Emacs maintainers to add support for this, but it has not made it into the main distribution yet.  File: w3.info, Node: vertical-align, Next: text-transform, Prev: text-decoration, Up: Text Properties vertical-align .............. This is currently unsupported in Emacs/W3.  File: w3.info, Node: text-transform, Next: text-align, Prev: vertical-align, Up: Text Properties text-transform .............. Supported none Values: Unsupported capitalize | uppercase | lowercase Values: Initial: none Applies to: all elements Inherited: yes Percentage N/A values: 'capitalize' Uppercases the first character of each word. 'uppercase' Uppercases all letters of the element. 'lowercase' Lowercases all letters of the element. 'none' Neutralizes inherited value. The actual transformation in each case is human language dependent. H1 { text-transform: uppercase } The example above would put 'H1' elements in uppercase text. NOTE: This capability was in the previous version of Emacs/W3, but has not been reimplemented in the new display code yet. Please feel free to send me patches.  File: w3.info, Node: text-align, Next: text-indent, Prev: text-transform, Up: Text Properties text-align .......... Value: left | right | center | justify Initial: User specific Applies to: block-level elements Inherited: yes Percentage N/A values: This property describes how text is aligned within the element. The actual justification algorithm used is UA and human language dependent. Example: DIV.center { text-align: center } Since 'text-align' inherits, all block-level elements inside the 'DIV' element with 'CLASS=center' will be centered. Note that alignments are relative to the width of the element, not the canvas.  File: w3.info, Node: text-indent, Next: line-height, Prev: text-align, Up: Text Properties text-indent ........... Not currently implemented in Emacs/W3.  File: w3.info, Node: line-height, Prev: text-indent, Up: Text Properties line-height ........... Not currently implemented in Emacs/W3.  File: w3.info, Node: Box Properties, Next: Classification, Prev: Text Properties, Up: Properties Box Properties --------------  File: w3.info, Node: Classification, Next: Media Selection, Prev: Box Properties, Up: Properties Classification -------------- These properties classify elements into categories more than they set specific visual parameters. The list-style properties describe how list items (i.e. elements with a 'display' value of 'list-item') are formatted. The list-style properties can be set on any element, and it will inherit normally down the tree. However, they will only be have effect on elements with a 'display' value of 'list-item'. In HTML this is typically the case for the 'LI' element. * Menu: * display:: * white-space:: * list-style-type:: * list-style-image:: * list-style-position:: * list-style::  File: w3.info, Node: display, Next: white-space, Prev: Classification, Up: Classification display ....... Value: block | inline | list-item | none Extensions: line Initial: inline Applies to: all elements Inherited: no Percentage N/A values: This property describes how/if an element is displayed on the canvas (which may be on a printed page, a computer display etc.). An element with a 'display' value of 'block' opens whitespace suitable for a paragraph break. Typically, elements like 'H1' and 'P' are of type 'block'. A value of 'list-item' is similar to 'block' except that a list-item marker is added. In HTML, 'LI' will typically have this value. An element with a 'display' value of 'inline' results in a new inline box on the same line as the previous content. A value of 'none' turns off the display of the element, including children elements and the surrounding box. P { display: block } EM { display: inline } LI { display: list-item } IMG { display: none } The last rule turns off the display of images. A value of 'line' results in a single line break. Emacs/W3 needs this extension to be able to fully specify the behaviour of BR and HR elements within a stylesheet. NOTE: Emacs/W3 defaults to using 'inline' for this property, which is a slight deviation from the specification.  File: w3.info, Node: white-space, Next: list-style-type, Prev: display, Up: Classification white-space ........... Value: normal | pre | nowrap Initial: normal Applies to: block-level elements Inherited: yes Percentage N/A values: This property declares how whitespace inside the element is handled: the 'normal' way (where whitespace is collapsed), as 'pre' (which behaves like the 'PRE' element in HTML) or as 'nowrap' (where wrapping is done only through BR elements): PRE { white-space: pre } P { white-space: normal }  File: w3.info, Node: list-style-type, Next: list-style-image, Prev: white-space, Up: Classification list-style-type ............... Value: disc | circle | square | decimal | lower-roman | upper-roman | lower-alpha | upper-alpha | none Initial: disc Applies to: elements with 'display' value 'list-item' Inherited: yes Percentage N/A values: This property is used to determine the appearance of the list-item marker if 'list-style-image' is 'none' or if the image pointed to by the URL cannot be displayed. Fo example: OL { list-style-type: decimal } /* 1 2 3 4 5 etc. */ OL { list-style-type: lower-alpha } /* a b c d e etc. */ OL { list-style-type: lower-roman } /* i ii iii iv v etc. */  File: w3.info, Node: list-style-image, Next: list-style-position, Prev: list-style-type, Up: Classification list-style-image ................ Value: | none Initial: none Applies to: elements with 'display' value 'list-item' Inherited: yes Percentage N/A values: This property sets the image that will be used as the list-item marker. When the image is available it will replace the marker set with the 'list-style-type' marker. NOTE: This is currently unimplemented in Emacs/W3. UL { list-style-image: url(http://png.com/ellipse.png) }  File: w3.info, Node: list-style-position, Next: list-style, Prev: list-style-image, Up: Classification list-style-position ................... Supported outside Values: Unsupported inside Values: Initial: outside Applies to: elements with 'display' value 'list-item' Inherited: yes Percentage N/A values: The value of 'list-style-position' determines how the list-item marker is drawn with regard to the content. For a formatting example see section 4.1.3.  File: w3.info, Node: list-style, Prev: list-style-position, Up: Classification list-style .......... Value: || || Initial: not defined for shorthand properties Applies to: elements with 'display' value 'list-item' Inherited: yes Percentage N/A values: The 'list-style' property is a shorthand notation for setting the three properties 'list-style-type', 'list-style-image' and 'list-style-position' at the same place in the style sheet. UL { list-style: upper-roman inside } UL UL { list-style: circle outside } LI.square { list-style: square } Setting 'list-style' directly on 'LI' elements can have unexpected results. Consider:
  1. level 1
    • level 2
Since the specificity (as defined in the cascading order) is higher for the first rule in the style sheet in the example above, it will override the second rule on all 'LI' elements and only 'lower-alpha' list styles will be used. It is therefore recommended to set 'list-style' only on the list type elements: OL.alpha { list-style: lower-alpha } UL { list-style: disc } In the above example, inheritance will transfer the 'list-style' values from 'OL' and 'UL' elements to 'LI' elements. A URL value can be combined with any other value: UL { list-style: url(http://png.com/ellipse.png) disc } In the example above, the 'disc' will be used when the image is unavailable.  File: w3.info, Node: Media Selection, Next: Speech Properties, Prev: Classification, Up: Properties Media Selection --------------- To specify that a stylesheet declaration should only apply when using a certain media type (ie: different font families preferred when printing versus on-screen presentation), the declarations should be wrapped in the proposed @media directive. The @media directive takes two arguments, the media type, and a block of style declarations. @media print { BODY { font-size: 10pt } H1 { font-size: 14pt } } The '@media' construct also allows to put include style sheet rules for various media in the same style sheet: @media print { BODY { font-size: 10pt } } @media screen { BODY { font-size: 12pt } } Currently, the following media types are defined. Print Output for paged opaque material, and for documents viewed on screen in print preview mode. Screen A continuous presentation for computer screens. Projector Paged presentation for projected presentations. Braille For braille tactile feedback devices. Speech Aural presentation. Light The stylesheet will only be applied if the user is using a light background. Dark The stylesheet will only be applied if the user is using a dark background. Emacs The stylesheet will only be applied if the user is running in Emacs 19. XEmacs The stylesheet will only be applied if the user is running in XEmacs 19. All The default value, the style sheet applies to all output devices.  File: w3.info, Node: Speech Properties, Prev: Media Selection, Up: Properties Speech Properties ----------------- Those of us who are sighted are accustomed to visual presentation of HTML documents, frequently on a bitmapped display. This is not the only possible presentation method, however. Aural presentation, using a combination of speech synthesis and 'audio icons', provides an alternative presentation. This form of presentation is in current use by the blind and print-impaired communities. Often such aural presentation occurs by converting the document to plain text and feeding this to a 'screen reader' - software or hardware that simply reads all the characters on the screen. This results in less effective presentation than would be the case if the document structure were retained. There are other large markets for aural presentation, including in-car and home entertainment use; aurual or mixed aural/visual presentation is thus likely to increase in importance over the next few years. Realizing that that the aural rendering is essentially independent of the visual rendering: * Allows orthogonal aural and visual views. * Allows browsers to optionally implement both aural and visual views to produce truly multimodal documents. * Menu: * volume:: * pause-before:: * pause-after:: * pause:: * cue-before:: * cue-after:: * cue:: * play-during:: * speed:: * voice-family:: * pitch:: * pitch-range:: * stress:: * richness:: * speak-punctuation:: * speak-date:: * speak-numeral:: * speak-time::  File: w3.info, Node: volume, Next: pause-before, Prev: Speech Properties, Up: Speech Properties volume ...... Value: | mute | x-soft | soft | medium | loud | x-loud Initial: medium Applies to: all elements Inherited: yes Percentage relative to user-specified mapping values: The legal range of percentage values is 0% to 100%. There is a fixed mapping between keyword values and percentages: * 'x-soft' = '0%' * 'soft' = '25%' * 'medium' = '50%' * 'loud' = '75%' * 'x-loud' = '100%' Volume refers to the median volume of the waveform. In other words, a highly inflected voice at a volume of 50 might peak well above that. Note that '0%' does not mean the same as "mute". 0% represents the minimum audible volume level and 100% corresponds to the maximum comfortable level. The UA should allow the values corresponding to 0% and 100% to be set by the user. Suitable values depend on the equipment in use (speakers, headphones), the environment (in car, home theater, library) and personal preferences. Some examples: * A browser for in-car use has a setting for when there is lots of background noise . 0% would map to a fairly high level and 100% to a quite high level. The overall values are likely to be human adjustable for comfort, for example with a physical volume control: what this proposal does is adjust the dynamic range. * Another speech browser is being used in the home, late at night, (don't annoy the neighbors) or in a shared study room. 0% is set to very quiet and 100% to a fairly quiet level, too. As with the first example, there is a low slope; the dynamic range is reduced. The actual volumes are low here, wheras they were high in the first example. * In a quiet and isolated house, an expensive hifi home theatre setup. 0% is set fairly low and 100% to quite high; there is wide dynamic range. The same authors stylesheet could be used in all cases, simply by mapping the 0 and 100 points suitably at the client side.  File: w3.info, Node: pause-before, Next: pause-after, Prev: volume, Up: Speech Properties pause-before ............ Value: