69 captures

14 Oct 2008 - 15 Feb 2026

Aug	SEP	Oct
	23
2008	2009	2010

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About this capture

COLLECTED BY

Organization: Alexa Crawls

Starting in 1996, Alexa Internet has been donating their crawl data to the Internet Archive. Flowing in every day, these data are added to the Wayback Machine after an embargo period.

Collection: alexa_web_2009

this data is currently not publicly accessible.

TIMESTAMPS

SIMPLE STYLE SHEETS
FOR SGML & HTML
ON THE WEB

World-Wide Web conference spring 1995
Developer's day --- 14 April 1995
Darmstadt

Context: Argo browser

• HTML viewer applet
• inline images handled by different applets
• upgrading to new formats is cheap

The HTML applet

1. real-time ``live'' formatting

   Seems to be the trend: Netscape, HotJava, Arena

2. implementation:

   FormattedText widget --
   SimpleSGML widget --
   HTML2 widget

   (widgets will become public in a few days)

Widget hierarchy (1)

• list of ``chunks'' (atomic units): words, hor. spaces (fixed or strechable), vert. spaces, parshapes, inline widgets
• 3 ``tracks'': main, left floats, right floats
• NB. nothing specific to SGML/HTML

• parser for simple SGML (``canonical form'', see Sperberg-McQueen & Goldstein)
• parser for stylesheets (actually Xlib/Xrm does most of the work)
• uses stack of styles, produces sequence of ``chunks''

Widget hierarchy (2)

• overrides some methods:
  • heuristic rules for omitted tags
  • more entities (WWW icon entities) [nyi]
  • forms (as inline objects) [nyi]
• currently accepts a mixture of HTML2 and HTML3
• NB. does no parsing

Assumptions (1)

1. Addressable units
   • whole elements only
   • by context or by ID
2. style sheet is static (declarative)
3. style sheet consists of rules; rules consist of: selector + property + value; value may be an expression
4. attributes not in selector, but in expression

Assumptions (2)

1. text is rendered roughly in the order it is received (exception: tables, math)
2. only appearrance specified, not interaction
3. SGML, not just HTML

Stream-based SS vs DSSSL

• Complementary!
• DSSSL needed for more complex layouts (re-arranging of text, columns)
• 2 (or more) links in a document?
  <LINK HREF="..." REL=STYLE NOTATION="...DSSSL...">
  <LINK HREF="..." REL=STYLE NOTATION="...W3O style...">

User preferences

Select 1, 2 or all 3

Combined just like X resources (override, replace, merge)

• pro:
  • flexible
  • already widely used
• con:
  • not always intuitive
  • maybe too flexible?

Style properties (1)

empty (*IMG.empty: true)

• needed by parser (omitted end tag)

emphasis (*STRONG.emphasis: 2)

• level of emphasis (at least 0, 1 2)
• allows browser to choose best method
• is this needed?

Style properties (2)

background (*A.textbackground: yellow)

• behind text only
• looks funny for longer, unjustified text
• maybe need separate background for paragraphs?

prebreak, postbreak (*P.postbreak: 0.0)

• break line, then insert vert. whitespace
• measured in ``standard line heights''
• maybe add units (mm, ex, pixels)?

Style properties (3)

leftindent, rightindent (*BQ.leftindent: 4.0)

• added to inherited margin
• measured in ``standard em'' (rel. to default font)
• measured from edge, discarding floats

track (*FIG.track: !ALIGN)

• 3 tracks: main, left/right float areas
• do we need more? (footnote, running head)
• NB ``title'' is not a track

Style properties (4)

minimized (*FOOTNOTE.minimized: true)

• contents are ``folded'' or put into pop-up
• different from hide

keepwidth (*CAPTION.keepwidth: true)

• tries to determine width of float from previous line
• not completely satisfactory: caption cannot precede figure

Style properties (5)

id (*id: !ID)

• assigns ID to an element
• usually taken from attribute
• allows assigning styles to individual element instances

insertbefore, insertafter (*CENTER.insertbefore: <DIV ALIGN=CENTER>)

• insert arbitrary text
• can be used to define new tags

math

• is currently unspecified :-(

Expressions

IDs

*@par12*EM.bold: true

an EM within an elt. with ID = ``par12''

attributes

*track: !ALIGN

value taken from ALIGN attribute

conditional

*flush: @ifmatch(!CLEAR, "[Ff].*", "both", !CLEAR)

2nd arg. is reg. exp.

More general expressions needed (in particular concatenation)

External influences

Cf. Cascading stylesheets and DSSSL (``length spec'')

• width of window
• age of document
• number of available colours
• user's history
• ...

Currently none specified

Odds & ends

• breakable, but invisible (cf. &shy;)
• in Unicode, but not in ISO :-(
• replaces Netscape's <WBR>

External vs in-line style sheets

• <LINK> vs <STYLE>
• priority?
• in-line handy for one-time styles

Other output formats

• Postscript, TeX, plain text,...