Acorn Browse HTML Support

Document Status

Distribution:   General Release
Title:   Acorn Browse HTML support
Drawing Number:   1216,211/T
Issue:   1
Author(s):   Andrew Hodgkinson
Date:   07/09/1998
Revision:   1.00
Change Number:   N/A
Last Issue:   N/A

Contents

  1. Document Status
  2. Issue / Revision History

  3. Supported Elements
  4. Supported Entites
  5. Supported Colours
  6. Broken HTML

  7. Further reading

    1. HTML 4.0 Specification
    2. Acorn Browse Plug-In Handling Description

Issue / Revision History

Issue 1 (General release)
1.00 07/09/1998 Created, using JavaScript in places since this allows easy maintenance base on application source code (ADH)

This document uses JavaScript. A non-JavaScript version is available, but note that the copy you are reading now is the master - compare dates to see how up to date the non-JavaScript version is.

Supported Elements

The browser's parser recognises the following set of elements and the browser itself will act on the following element attributes:

ElementAttributes
A  coords href name shape target
ACRONYM  None
ADDRESS  n/a
APPLET  align [1] alt code codebase height hspace object vspace width
AREA  alt coords href shape target
B  n/a
BASE  href target
BASEFONT  color [4] size
BIG  n/a
BLINK  [2]
BLOCKQUOTE n/a
BODY  alink background [6] bgcolor [4] link text vlink
BR  n/a
CENTER  [4]
CITE  n/a
CODE  n/a
DD  n/a
DEL  n/a
DFN  n/a
DIR  [2]
DIV  align [4]
DL  None
DT  n/a
EM  n/a
EMBED  align [1] height src width
FONT  n/a
FORM  action method target
FRAME  bordercolor [4] name noresize scrolling src
FRAMESET  border bordercolor [4] cols frameborder framespacing rows
H1  align
H2  align
H3  align
H4  align
H5  align
H6  align
HEAD  n/a
HR  align noshade size width
I  n/a
IMG  align [1] alt border height hspace ismap src [6] usemap vspace width
INPUT  align [5] alt checked maxlength name size src [6] type usemap value
INS  n/a
ISINDEX  [2]
KBD  n/a
LI  None
LINK  [2]
MAP  name
MENU  None
META  content http-equiv [3]
NOBR  [2]
NOFRAMES  n/a
NOSCRIPT  n/a
OBJECT  align [1] border classid codebase codetype data height hspace name shapes standby type usemap vspace width
OL  start type
OPTION  selected value
P  align [4]
PARAM  id name type value valuetype
PRE  n/a
Q  n/a
S  n/a
SAMP  n/a
SCRIPT  None
SELECT  multiple size
SMALL  n/a
STRIKE  n/a
STRONG  n/a
STYLE  [2]
SUB  n/a
SUP  n/a
TABLE  align [1] bgcolor [4] border cellpadding cellspacing height width
TD / TH  align bgcolor [4] colspan height rowspan valign [4] width
TEXTAREA  cols rows
TITLE  n/a
TR  align bgcolor [4] colspan height rowspan valign [4] width
TT  n/a
U  n/a
UL  n/a
VAR  n/a
XMP  [5]

Footnotes from the above table:

  1. Alignment - Browse does not support floating objects, so text cannot flow around images and navigation tables cannot float next to content tables for example. It will attempt to at least align objects centred or to the left or right margin where possible. See [4] also.
  2. Unsupported - The browser does nothing with this element.
  3. META - only used for client pull presently.
  4. UK English - for some common items Browse will recognise UK and 'American English' spellings, e.g. "color" and "colour", "center" and "centre".
  5. Partial support - Some values may not work as expected (typically alignment specification).
  6. Internal URLs - Navigator (but not MSIE) knows certain "magic" URLs such as 'internal-gopher-image'. Web proxies have been known to pass these out to people using FTP through them. Browse does not support these magic values.

Supported Entities

The full range of HTML 4 entities are supported.

The following table is generated with JavaScript using a fragment of a source file from the HTML parser. The Unicode values are listed in hex. If the browser you are using does not support JavaScript, this isn't really a problem as the list of supported colours is self-evident from the script source.

Supported Colours

The following table of colours is generated with JavaScript using a fragment of a source file from the HTML parser. The red, green and blue values are listed in hex. If the browser you are using does not support JavaScript, this isn't really a problem, as the list of supported colours is self-evident from the script source.

Broken HTML

The browser will cope with a variety of types of broken HTML, not least of which includes incorrect structure (documents with TITLE inside BODY sections and so-forth). The measures detailed below have been arrived at over a lengthy development cycle where behaviour of Navigator, Internet Explorer, and other browsers is compared on various sites which failed in Browse. Over time, the parser and browser have become progressively more robust to broken HTML, though there is always work to do to improve this.

Steps taken include:

This is not a complete list, but it covers the most important things.

Further Reading

The following may be of interest.

HTML 4.0 Specification
The "horse's mouth" description of current HTML at the time of writing.
Acorn Browse Plug-In Handling Description
A description of the way that the browser invokes plug-ins.
Last updated 5 October 1998
© Acorn Computers Limited, 1997
Valid HTML 4.0