layout/doc/obsolete/nav4-html.html

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   4
   5 <HTML>
   6 <HEAD>
   7    <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
   8    <META NAME="Author" CONTENT="Kipp E.B. HIckman">
   9    <META NAME="GENERATOR" CONTENT="Mozilla/4.03 [en] (WinNT; I) [Netscape]">
  10    <TITLE>HTML</TITLE>
  11    <BASE HREF="file:///s|/ns/xena/htmlpars/testhtml/">
  12 </HEAD>
  13 <BODY TEXT="#000000" BGCOLOR="#FFFFFF" LINK="#FF0000" VLINK="#800080" ALINK="#0000FF">
  14
  15 <H2>
  16 HTML</H2>
  17 This documents describes the complete handling of HTML in magellan. The
  18 document covers the parsing process - how HTML is lexically analysized
  19 and then interprted. After the parsing process is discussed we give a detailed
  20 analysis of each HTML tag and the attributes that are supported, the values
  21 for the attributes and how the tag is treated by magellan.
  22 <H2>
  23 Parsing</H2>
  24 HTML is tokenized by an HTML scanner. The scanner is fed unicode data to
  25 parse. Stream converters are used to translate from various encodings to
  26 unicode. The scanner separates the input stream into tokens which consist
  27 of:
  28 <UL>
  29 <LI>
  30 text</LI>
  31
  32 <LI>
  33 tags</LI>
  34
  35 <LI>
  36 entities</LI>
  37
  38 <LI>
  39 script-entities</LI>
  40
  41 <LI>
  42 comments</LI>
  43
  44 <LI>
  45 conditional comments</LI>
  46 </UL>
  47 The HTML parsing engine uses the HTML scanner for lexical anlaysis. The
  48 parsing engine operates by attacking the input stream in a set of well
  49 defined steps:
  50 <UL>
  51 <LI>
  52 The parser processes the head portion of the document first, without emitting
  53 any output. This is done to discover a few special features of html:</LI>
  54
  55 <UL>
  56 <LI>
  57 The parser processes META tags looking for META TARGET</LI>
  58
  59 <LI>
  60 The parser processes META tags looking for META tags which affect the character
  61 set. Nav4 handles the very first character set defining meta tag (all others
  62 are ignored) by reloading the document with the proper character conversion
  63 module inserted into the stream pipeline.</LI>
  64 </UL>
  65
  66 <LI>
  67 After the head portion is processed the parser then proceeds to process
  68 the body of the document</LI>
  69 </UL>
  70
  71 <H3>
  72 Tag Processing</H3>
  73 Tags are processed by the parser by locating a <B>"tag handler"</B> for
  74 the tag. The HTML parser serves as the tag handler for all of the builtin
  75 tags documented below. Tag attribute handling is done during translation
  76 of tags into content. This mapping translates the tag attributes into content
  77 data and into style data. The translation to style data is documented below
  78 by indicating the mapping from tag attributes to their CSS1 (plus extensions)
  79 equivalents.
  80 <H3>
  81 Special Hacks</H3>
  82 The following list describes hacks added to the magellan parsing engine
  83 to deal with navigator compatibility. These are just the parser hacks,
  84 not the layout or presentation hacks. Most hacks are intriduced for HTML
  85 syntax error recovering. HTML doesn't specify much how to handle those
  86 error conditions. Netscape has made big effort to render pages with non-prefect
  87 HTML. For many reasons, new browsers need to keep compatible in thsi area.
  88 <UL>
  89 <LI>
  90 Entities can be used as escape in quoted string. For value string in name-value
  91 pair,&nbsp; see <A HREF="../testhtml/quote001.html">compatibility test
  92 quote001.html</A>. Test line 70 shows that an entity quote at the begining
  93 means the value is NOT quoted. Test line 90 shows that if the value is
  94 started with a quote, then an entity quote does NOT terminate the value
  95 string.</LI>
  96
  97 <LI>
  98 Wrapping tags are special tags such as title, textarea, server, script,
  99 style, and etc.. The comment in ns\lib\libparse\pa_parse.c says:</LI>
 100
 101 <BR>&nbsp; /*
 102 <BR>&nbsp;&nbsp; * These tags are special in that, after opening one of
 103 them, all other tags are ignored until the matching
 104 <BR>&nbsp;&nbsp; * closing tag.
 105 <BR>&nbsp;&nbsp; */
 106 <BR>During the searching of an end tag, comments and quoted strings are
 107 observed. see <A HREF="../testhtml/title01.html">compatibility test title01.html</A>.
 108 6.0 handles comments now, need to add quoted string.
 109 <LI>
 110 If a &lt;tr> or &lt;td> tag is seen outside any &lt;table> scope, it is
 111 ignored. see <A HREF="../testhtml/table110.htm">compatibility test table110.htm</A>.</LI>
 112
 113 <LI>
 114 <FONT COLOR="#000000">In case of table in table but not in cell, table
 115 tags before the last table tag are ignored. We found this problem in some
 116 Netscape public pages, see bug #85118. For example, &lt;table> &lt;table
 117 border> .....,or &lt;table> &lt;tr> &lt;table border>...,&nbsp; the table
 118 will be displayed with border.&nbsp;</FONT> <A HREF="../testhtml/table201.html">compatibility
 119 test table201.html</A>. There table and tr tags are buffered for this recovery.
 120 When a TD or CAPTION tag is open, the buffer is flushed out, because we
 121 cannot buffer contents of TD or CAPTION for performance and memory constrains.
 122 They are subdoc's and can be very big. If we see a &lt;table> outside cell
 123 after previous table is flushed out, the new &lt;table> tag is ignored.
 124 Nav4.0 can discard previous table in such case. <A HREF="../testhtml/tableall.html">tableall.html
 125 </A>is the index for table test cases.</LI>
 126
 127 <LI>
 128 Caption is not a commonly used feature. In Nav4.0, captions can be anywhere.
 129 For Captions outside cells, the first one takes effect. For captions inside
 130 cells, the last one takes effect, and they also close TD and TR. In 6.0,
 131 caption is limited to the standard position: after &lt;table>. Captions
 132 in other places are ignored, their contents are treated as text. See test
 133 case table05a.html to table05o.html.</LI>
 134
 135 <LI>
 136 <FONT COLOR="#000000">For &lt;table> &lt;tr> &lt;tr>, the first &lt;tr>
 137 takes effect.</FONT></LI>
 138
 139 <LI>
 140 The nav4 parser notices when it hits EOF and it's in the middle of scanning
 141 in a comment. When this happens, the parser goes back and looks for an
 142 improperly closed comment (e.g. a simple > instead of a -->). If it finds
 143 one, it reparses the input after closing out the comment.</LI>
 144
 145 <LI>
 146 <FONT COLOR="#FF0000">XXX Brendan also pointed out that there is something
 147 similar done for tags, but I don't recall what it is right now.</FONT></LI>
 148
 149 <LI>
 150 <FONT COLOR="#000000">When Nav4.0 sees the '&lt;' sign, it searchs for
 151 '>', observing quoted values. If it cannot find one till EOF, the '&lt;'
 152 sign is treated as text. In Xena 6.0, a limit is set for how far the '>'
 153 is searched. the default limit is 4096 char, and there is a API HTMLScanner.setMaxTagLength()
 154 to changed it. setting -1 means no limit, which is same as Nav4.0.</FONT></LI>
 155 </UL>
 156 <FONT COLOR="#FF0000">TODO:</FONT>
 157 <UL><FONT COLOR="#FF0000">Document the mapping of tag attributes into CSS1
 158 style, including any new "css1" attributes</FONT>
 159 <BR>&nbsp;</UL>
 160 <B>List of 6.0 features incompatible with 4.0</B>
 161 <UL>
 162 <LI>
 163 Navigator 4.0 value string is truncated at 82 characters. XENA60 limit
 164 is MAX_STRING_LENGTH = 2000.</LI>
 165
 166 <BR>&nbsp;</UL>
 167
 168 <HR WIDTH="100%">
 169 <H2>
 170 Tags (Categorically sorted)</H2>
 171 All line breaks are conditional. If the x coordinate is at the current
 172 left margin then a soft line break does nothing. Hard line breaks are ignored
 173 if the last tag did a hard line break.
 174
 175 <P><B>divalign</B> = left | right | center | justify
 176 <BR><B>alignparam</B> = abscenter | left | right | texttop | absbottom
 177 | baseline | center | bottom | top | middle | absmiddle
 178 <BR><B>colorspec</B> = named-color | #xyz | #xxyyzz | #xxxyyyzzz | #xxxxyyyyzzzz
 179 <BR><B>clip</B> = [auto | value-or-pct-xy](1..4) (pct of width for even
 180 coordinates; pct of height for odd coordinates)
 181 <BR><B>value-or-pct = </B>an integer with an optional %; ifthe percent
 182 is present any following characters are ignored!
 183 <BR><B>coord-list</B> = <FONT COLOR="#DD0000">XXX</FONT>
 184 <BR><FONT COLOR="#000000"><B>whitespace-strip</B> = remove leading and
 185 trailing and any embedded whitespace that is not an actual space (e.g.
 186 newlines)</FONT>
 187 <H1>
 188 Head objects:</H1>
 189 <B>TITLE</B>
 190 <UL>The TITLE tag is a container tag whose contents are not HTML. The contents
 191 are pure text and are processed by the parser until the closing tag is
 192 found. There are no attributes on the tag and any whitespace present in
 193 the tag is compressed down with leading and trailing whitespace eliminated.
 194 The first TITLE tag found by the parser is used as the document's title
 195 (subsequent tags are ignored).</UL>
 196 <B>BASE</B>
 197 <UL>Sets the base element in the head portion of the document. Defines
 198 the base URL for <FONT COLOR="#DD0000">all</FONT>? links in the document.
 199 <BR>Attributes:
 200 <UL><B>HREF</B>=url [This is an absolute URL]
 201 <BR><B>TARGET</B>=string [must start with XP_ALPHA|XP_DIGIT|underscore
 202 otherwise nav4 ignores it]</UL>
 203 </UL>
 204 <B>META</B>
 205 <UL>Can define several header fields (content-encoding, author, etc.)
 206 <BR>Attributes:
 207 <UL><B>REL</B>=SMALL_BOOKMARK_ICON|LARGE_BOOKMARK_ICON
 208 <UL><B>SRC</B>=string</UL>
 209 <B>HTTP-EQUIV</B>="header: value"
 210 <UL><B>CONTENT</B>=string</UL>
 211 </UL>
 212 HTTP-EQUIV values (from libnet/mkutils.c NET_ParseMimeHeader):
 213 <UL>ACCEPT-RANGES
 214 <BR>CONTENT-DISPOSITION
 215 <BR>CONTENT-ENCODING
 216 <BR>CONTENT-RANGE
 217 <BR>CONTENT-TYPE [ defines character set only ]
 218 <BR>CONNECTION
 219 <BR>DATE
 220 <BR>EXPIRES
 221 <BR>EXT-CACHE
 222 <BR>LOCATION
 223 <BR>LAST-MODIFIED
 224 <BR>LINK
 225 <BR>PROXY-AUTHENTICATE
 226 <BR>PROXY-CONNECTION
 227 <BR>PRAGMA
 228 <BR>RANGE
 229 <BR>REFRESH
 230 <BR>SET-COOKIE
 231 <BR>SERVER
 232 <BR>WWW-AUTHENTICATE
 233 <BR>WWW-PROTECTION-TEMPLATE
 234 <BR>WINDOW-TARGET</UL>
 235 Style sheets and HTML w3c spec adds this:
 236 <UL>CONTENT-STYLE-TYPE [ last one wins; overrides header from server if
 237 any ]</UL>
 238 </UL>
 239 <B>LINK</B>
 240 <UL>List related resources. Used by extensions mechanism to find tag handlers.
 241 <FONT COLOR="#0000FF">/LINK == LINK!</FONT>
 242 <BR>Attributes:
 243 <UL><B>REL</B>=FONTDEF
 244 <UL><B>SRC</B>=url</UL>
 245 <B>REL</B>=STYLESHEET [ If MEDIA param is defined it must ==nc screen ]
 246 <UL><B>LANGUAGE</B>=LiveScript|Mocha|JavaScript1.1|JavaScript1.2
 247 <BR><B>TYPE</B>="text/javascript" | "text/css"
 248 <BR><B>HREF</B>=url
 249 <BR><B>ARCHIVE</B>=url
 250 <BR><B>CODEBASE</B>=url
 251 <BR><B>ID</B>=string
 252 <BR><B>SRC</B>=url</UL>
 253 </UL>
 254 Note: HREF takes precedence over SRC in nav4.</UL>
 255 <B>HEAD</B>
 256 <UL>/HEAD clears the "in_head" flag (but leaves the "in_body" flag alone.
 257 <BR>Text in head clears in_head, and set in_body true, just as if the author
 258 forgot the /HEAD tag.
 259 <BR>Attributes: none</UL>
 260 <B>HTML</B>
 261 <UL>Ignored.
 262 <BR>Attributes: none</UL>
 263 <B>STYLE</B>
 264 <UL>Allowed anywhere in the document. Note that entities are not parsed
 265 in the style tag's content.
 266 <BR>Attributes:
 267 <UL><B>LANGUAGE</B>=LiveScript|Mocha|JavaScript1.1|JavaScript1.2
 268 <BR><B>TYPE</B>="text/javascript" | "text/css"
 269 <BR><B>HREF</B>=url
 270 <BR><B>ARCHIVE</B>=url
 271 <BR><B>CODEBASE</B>=url
 272 <BR><B>ID</B>=string
 273 <BR><B>SRC</B>=url</UL>
 274 </UL>
 275 <B>FRAMESET</B>
 276 <UL>Frameset with rows=1 and cols=1 is ignored.
 277 <BR>Attributes:
 278 <UL><B>FRAMEBORDER</B>= no | 0 (zero) [default is no_edges=false]
 279 <BR><B>BORDER</B>= int [clamped: >= 0 &amp;&amp; &lt;= 100]
 280 <BR><B>BORDERCOLOR</B>= color
 281 <BR><B>ROWS</B>= pct-list
 282 <BR><B>COLS</B>= pct-list</UL>
 283 </UL>
 284 <B>FRAME</B>
 285 <UL>Border width of zero disables edges.
 286 <BR>Attributes:
 287 <UL><B>FRAMEBORDER</B>= no | 0 (zero) [default is framesets value]
 288 <BR><B>BORDER</B>= int [clamped; >= 0 &amp;&amp; &lt;= 100]
 289 <BR><B>BORDERCOLOR</B>= color
 290 <BR><B>NORESIZE</B>= true [default is false]
 291 <BR><B>SCROLLING</B>= yes | scroll | on | no | noscroll | off
 292 <BR><B>SRC</B>= url [clamped: prevent recursion by eliminating any anscestor
 293 references]
 294 <BR><B>NAME</B>= string
 295 <BR><B>MARGINWIDTH</B>= int (clamped: >= 1)
 296 <BR><B>MARGINHEIGHT</B>= int (clamped: >= 1)</UL>
 297 </UL>
 298 <B>NOFRAMES</B>
 299 <UL>Used when frames are disabled or for backrev browsers. Has no stylistic
 300 consequences.</UL>
 301
 302 <H1>
 303
 304 <HR WIDTH="100%">Body objects:</H1>
 305 &nbsp;<B>BODY</B>
 306 <UL>The tag is only processed on open tags and it is always processed.
 307 See ns\lib\layout\laytags.c, searching for "case P_BODY". During tag processing
 308 the in_head flag is set to false and the in_body flag is set to true. An
 309 attribute is ignored if the document already has that attribute set. Attributes
 310 can be set by style sheets, or by previous BODY tags. see <A HREF="../testhtml/head02.html">test
 311 head02.html</A>.
 312 <BR>Attributes:
 313 <UL><B>MARGINWIDTH</B>=int [clamped: >= 0 &amp;&amp; &lt; (windowWidth/2
 314 - 1)]
 315 <BR><B>MARGINHEIGHT</B>=int [clamped: >= 0 &amp;&amp; &lt; (windowHeight/2
 316 - 1)]
 317 <BR><B>BACKGROUND</B>=url
 318 <BR><B>BGCOLOR</B>=colorspec
 319 <BR><B>TEXT</B>=colorspec
 320 <BR><B>LINK</B>=colorspec
 321 <BR><B>VLINK</B>=colorspec
 322 <BR><B>ALINK</B>=colorspec
 323 <BR><B>ONLOAD, ONUNLOAD, UNFOCUS, ONBLUR, ONHELP</B>=script
 324 <BR><B>ID</B>=string</UL>
 325 </UL>
 326 <B>LAYER, ILAYER</B>
 327 <UL>Open layer/ilayer tag automaticly close out an open form if one is
 328 open. It does something to the soft linebreak state too.
 329 <BR>Attributes:
 330 <UL><B>LEFT</B>=value-or-pct (pct of <TT>right-left</TT> margin)
 331 <BR><B>PAGEX</B>=x (if no LEFT)
 332 <BR><B>TOP</B>=value-or-pct
 333 <BR><B>PAGEY</B>=y (if no TOP)
 334 <BR><B>CLIP</B>=clip
 335 <BR><B>WIDTH</B>=value-or-pct (pct of <TT>right-left</TT> margin)
 336 <BR><B>HEIGHT</B>=value-or-pct
 337 <BR><B>OVERFLOW</B>=string
 338 <BR><B>NAME</B>=string
 339 <BR><B>ID</B>=string
 340 <BR><B>ABOVE</B>=string
 341 <BR><B>BELOW</B>=string
 342 <BR><B>ZINDEX</B>=int [any value]
 343 <BR><B>VISIBILITY</B>=string
 344 <BR><B>BGCOLOR</B>=colorspec
 345 <BR><B>BACKGROUND</B>=url</UL>
 346 </UL>
 347 <B>NOLAYER</B>
 348 <UL>Container for content which is used when layers are disabled or unsupported.
 349 The content has no style consequences (though it could if somebody stuck
 350 in some CSS1 style rules for it).</UL>
 351 <B>P</B>
 352 <UL>Closes the paragraph. If the attribute is present then an alignment
 353 gets pushed on the alignment stack. All values are supported by nav4.
 354 <BR>Attributes:
 355 <UL><B>ALIGN</B>=divalign</UL>
 356 </UL>
 357 <B>ADDRESS</B>
 358 <UL>There are no attributes. ADDRESS closes out the open paragraph. The
 359 open tag does a conditional soft line break and then pushes a merge of
 360 the current style with italics enabled onto the style stack. The close
 361 always pop the style stack and also does a conditional soft line break.</UL>
 362 <B>PLAINTEXT, XMP</B>
 363 <UL>PLAINTEXT causes the remaining content to no longer be parsed. XMP
 364 causes the content to not parse entities or other tags. The XMP can be
 365 closed by it's own tag (on any boundary); PLAINTEXT is not closed (html3.2
 366 allows it to be closed). Both tags change the style to a fixed font of
 367 a</UL>
 368 <B>LISTING</B>
 369 <UL>Closes the paragraph. Does a hard line break on open and close. Open
 370 pushes a fixed width font style of a particular font size on the style
 371 stack. The close tag pops the top of the style stack.
 372 <BR>Attributes: none</UL>
 373 <B>PRE</B>
 374 <UL>Closes the paragraph. The open tag does a hard line break. A fixed
 375 font style (unless VARIABLE is present) is pushed on the style stack. The
 376 close tag pops the top of the style stack. It also does a hard line break.
 377 <BR>Attributes:
 378 <UL><B>WRAP</B>
 379 <BR><B>COLS</B>=int [clamped: >= 0]
 380 <BR><B>TABSTOP</B>=int [clamped: >= 0; clamped value is replaced with default
 381 value]
 382 <BR><B>VARIABLE</B></UL>
 383 </UL>
 384 <B>NOBR</B>
 385 <UL>This tag doesn't nest. Instead it just sets or clears a flag in the
 386 state machine. It has no effect on any other state.</UL>
 387 <B>CENTER</B>
 388 <UL>Closes the paragraph. Always does a conditional soft line break. The
 389 open tag pushes an alignment on the aligment stack. The close tag pops
 390 the top alignment off.
 391 <BR>Attributes: none</UL>
 392 <B>DIV</B>
 393 <UL>Closes the paragraph. Always does a conditional soft line break. COLS
 394 defines the number of columns to layout in (like MULTICOL). The open tag
 395 pushes an alignment on the alignment stack (if COLS > 1 then it pretends
 396 to be a MULTICOL tag). The close tag pops an aligment from the alignment
 397 stack.
 398 <BR>Attributes:
 399 <UL><B>ALIGN</B>=divalign
 400 <BR><B>COLS</B>=int [if cols > 1 then DIV acts like a MULTICOL tag else
 401 DIV is just a container]
 402 <UL><B>GUTTER</B>= int (clamped: >= 1)
 403 <BR><B>WIDTH</B>= value-or-pct [pct of right-left margin; clamped >= 1/0
 404 (strange code)]</UL>
 405 </UL>
 406 </UL>
 407 <B>H1-H6</B>
 408 <UL>Closes the paragraph. The open tag does a hard line break and pushes
 409 a style item which enables bold and disables fixed and italic. The close
 410 tag always pops the top item from the style stack. It also does a hard
 411 line break. If the <B>ALIGN</B> attribute is present then the open tag
 412 pushes an alignment on the alignment stack. The close tag will look at
 413 the top of the alignment stack and if its a header of any kind (H1 through
 414 H6) then the alignment is popped. In either case the close tag also does
 415 a conditional soft line break (this happens before the hard line break).
 416 <BR>Attributes:
 417 <UL><B>ALIGN</B>=divalign</UL>
 418 </UL>
 419 A note regarding closing paragraphs: Any time a close paragraph is done
 420 (for any tag) if the top of the alignment stack has a tag named "P" then
 421 a conditional soft line break is done and the alignment is popped.
 422 <H3>
 423
 424 <HR ALIGN=LEFT WIDTH="50%"></H3>
 425 <B>TABLE</B>
 426 <UL>Close the paragraph.
 427 <BR>Attributes:
 428 <UL><B>ALIGN=</B>left|right|center|abscenter
 429 <BR><B>BORDER</B>=int [clamped: if null then -1, if &lt; 1 then 1 ]
 430 <BR><B>BORDERCOLOR</B>=string [if not supplied then set to the text color
 431 ]
 432 <BR><B>VSPACE</B>=int [ clamped: >= 0 ]
 433 <BR><B>HSPACE</B>=int [ clamped: >= 0 ]
 434 <BR><B>BGCOLOR</B>=color
 435 <BR><B>BACKGROUND</B>=url
 436 <BR><B>WIDTH</B>=value-or-pct [ % of win.width minus margins; clamped:
 437 >= 0 ]
 438 <BR><B>HEIGHT</B>=value-or-pct [ % of win.height minus margins; clamped:
 439 >= 0 ]
 440 <BR><B>CELLPADDING</B>=int [clamped: >= 0; separate pads take precedence
 441 ]
 442 <BR><B>TOPPADDING</B>= int [clamped: >= 0 ]
 443 <BR><B>BOTTOMPADDING</B>= int [clamped: >= 0 ]
 444 <BR><B>LEFTPADDING</B>= int [clamped: >= 0 ]
 445 <BR><B>RIGHTPADDING</B>= int [clamped: >= 0 ]
 446 <BR><B>CELLSPACING</B>= int [clamped: >= 0 ]
 447 <BR><B>COLS</B>=int [clamped: >= 0]</UL>
 448 The code supports more attributes in the Table attribute handler than it
 449 does in the code that gets the attributes from the tag! They are border_top,
 450 border_left, border_right, border_bottom, border_style (defaults to outset;
 451 allows for outset/dotted/none/dashed/solid/double/groove/ridge/inset).</UL>
 452 <B>TR</B>
 453 <UL>Open TR automatically closes an open table row (and an open table cell
 454 if one is open). It also automatically closes a CAPTION tag.
 455 <BR>Attributes:
 456 <UL><B>BGCOLOR</B>=color
 457 <BR><B>BACKGROUND</B>=url
 458 <BR><B>VALIGN</B>=top|bottom|middle|center(==middle)|baseline; default
 459 is top
 460 <BR><B>ALIGN</B>=left|right|middle|center(==middle); default is left</UL>
 461 </UL>
 462 <B>TH, TD</B>
 463 <UL>If no table then the tag is ignored (open or close). If no row is currently
 464 opened or the current row is current done (because of a &lt;/TR> tag) then
 465 a new row is begun. Oddly enough the tag parameters for the row come from
 466 the TH/TD tag in this case. An open of either of these tags will automatically
 467 close the previous cell.
 468 <BR>Attributes:
 469 <UL><B>COLSPAN</B>=int [clamped: >= 1 &amp;&amp; &lt;= 1000 ]
 470 <BR><B>ROWSPAN</B>=int [clamped: >= 1 &amp;&amp; &lt;= 10000 ]
 471 <BR><B>NOWRAP</B> [boolean: disables wrapping ]
 472 <BR><B>BGCOLOR</B>=color [default: inherit from the row; if not row then
 473 table; if not table then inherit from an outer table cell; this works because
 474 the style is flattened so the outer table cell will have a color]
 475 <BR><B>BACKGROUND</B>=url [same rules as bgcolor for inheritance; tile
 476 mode is inherited too and not settable by TH/TD attributes (have to use
 477 style sheets for that)]
 478 <BR><B>VALIGN</B>=top|bottom|middle|center(==middle)|baseline; default
 479 is top
 480 <BR><B>ALIGN</B>=left|right|middle|center(==middle); default is left
 481 <BR><B>WIDTH</B>=value-or-pct [ clamped: >= 0 ]
 482 <BR><B>HEIGHT</B>=value-or-pct [ clamped: >= 0 ]</UL>
 483 </UL>
 484 <B>CAPTION</B>
 485 <UL>An open caption tag will automatically close an open table row (and
 486 an open cell).
 487 <BR>Attributes:
 488 <UL><B>ALIGN</B>=bottom</UL>
 489 The code sets the vertical alignment to top w/o providing a mechanism for
 490 the user to set it (there is no VALIGN attribute).</UL>
 491 <B>MULTICOL</B>
 492 <UL>The open tag does a hard line break. The close tag checks to see if
 493 the state machine has an open multicol and if it does then it does a conditional
 494 soft line break and then continues to break until both margins are cleared
 495 of floating elements. It recomputes the margins based on the list indenting
 496 level (?). After the synthetic table is output the close tag does a hard
 497 line break.
 498
 499 <P>This tag will treat the input as source for a table with one row and
 500 COLS columns. The data is laid out using the width divided by the number
 501 of columns. After the total height is known, the content is partitioned
 502 as evenly as possible between the columns in the table.
 503 <BR>Attributes:
 504 <UL><B>COLS</B>=int [clamped: values less than 2 cause the tag to be ignored]
 505 <BR><B>GUTTER</B>=int [clamped: >= 1]
 506 <BR><B>WIDTH</B>=value-or-pct [pct of right-left margin; clamped: >= 1/0
 507 (strange code)]</UL>
 508 </UL>
 509
 510 <H3>
 511
 512 <HR ALIGN=LEFT WIDTH="50%"></H3>
 513 <B>BLOCKQUOTE</B>
 514 <UL>Closes the paragraph. The open tag does a hard line break. A list with
 515 the empty-bullet style is pushed on the list stack (unless TYPE=cite/jwz
 516 then a styled list is pushed). The close tag pops any list and does a hard
 517 line break.
 518 <BR>Attributes:
 519 <UL><B>TYPE</B>=cite | jwz</UL>
 520 </UL>
 521 <B>UL, OL, MENU, DIR</B>
 522 <UL>For top-level lists (lists not in lists) a hard break is done on the
 523 open tag, otherwise a conditional-soft-break is done. Tag always does a
 524 close paragrah. The close tag does a conditional soft line break when nested;
 525 when not nested the close tag does a hard line break (even if no list is
 526 open). The open tag pushes the list on the list stack. The close tag pops
 527 any list off the list stack.
 528 <BR>Attributes:
 529 <UL><B>TYPE</B>= none | disc | circle | round | square | decimal | lower-roman
 530 | upper-roman | lower-alpha | upper-alpha | A | a | I | i [clamped: if
 531 none of the above is picked and OL then the bullet type is "number" otherwise
 532 the bullet type is "basic"]
 533 <BR><B>START</B>=int [clamped: >= 1]
 534 <BR><B>COMPACT</B></UL>
 535 </UL>
 536 <B>DL</B>
 537 <UL>Closes the paragraph. For the open tag, if the list is nested then
 538 a conditional soft line break is done otherwise a hard line break is done.
 539 The open tag pushes a list on the list stack. The close tag pops any list
 540 from the list stack. Closing the list acts like other lists closes.
 541 <BR>Attributes:
 542 <UL><B>COMPACT</B></UL>
 543 </UL>
 544 <B>LI</B>
 545 <UL>Closes the paragraph. The open tag does a conditional soft line break.
 546 Close tags are ignored (except for closing the paragraph).
 547 <BR>Attributes:
 548 <UL><B>TYPE</B>= A | a | I | i (if the containing list is an <B>OL</B>)
 549 <BR><B>TYPE</B>= round | circle | square (if the containing list is not
 550 <B>OL</B> and not <B>DL</B>)
 551 <BR><B>VALUE</B>=int [clamped: >= 1]</UL>
 552 The magellan html parser allows the full set of list item styles from the
 553 OL/DL tag instead of just the limited set that nav4 allows.</UL>
 554 <B>DD</B>
 555 <UL>Closes the paragraph. Close tags are ignored (except for closing the
 556 paragraph). DD outside a DL just advances the X coordinate of layout by
 557 a small constant. DD inside a DL does a conditional soft line break and
 558 other margin crud.
 559 <BR>Attributes: none.</UL>
 560 <B>DT</B>
 561 <UL>Closes the paragraph (open or close). Close tags are otherwise ignored.
 562 Does a conditional soft line break. Moves the X layout coordinate to the
 563 left margin.
 564 <BR>Attributes: none</UL>
 565
 566 <H3>
 567
 568 <HR ALIGN=LEFT WIDTH="50%"></H3>
 569 <B>A</B>
 570 <UL>Open anchors push a style on the style stack if the anchor has an <B>HREF</B>.
 571 Close anchors pop as many styles off the top of the style stack that are
 572 anchor tags (anchor tags don't nest in other words). In addition, any styles
 573 on the stack that have the ANCHOR bit set have it cleared and fiddle with
 574 the foreground and background colors.
 575 <BR>Attributes:
 576 <UL><B>NAME</B>=string
 577 <BR><B>HREF</B>=url
 578 <UL><B>TARGET</B>=target
 579 <BR><B>SUPPRESS</B>=true</UL>
 580 </UL>
 581 </UL>
 582 <B>STRIKE, S, TT, CODE, SAMPLE, KBD, B, STRONG, I, EM, VAR, CITE, BLINK,
 583 BIG, SMALL, U, INLINEINPUT, SPELL</B>
 584 <UL>The open tag pushes onto the style stack. The close tag always pops
 585 the top item from the style stack.
 586 <BR>Attributes: none</UL>
 587 <B>SUP, SUB</B>
 588 <UL>The open tag pushes a font size descrease on the style stack. The close
 589 tag always pops the top of the style stack. The open and close tag impacts
 590 the baselineThe only difference between SUP and SUB is how they impact
 591 the baseline. Note that the baseline information is forgotten after a line
 592 break; therefore a close SUP/SUB on the next line will do strange things.
 593 <BR>Attributes: none</UL>
 594 <B>SPAN</B>
 595 <UL>Ignored by the navigator.
 596 <BR>Attributes: none</UL>
 597 <B>FONT</B>
 598 <UL>The open font tag with no attributes resets the font size to the base
 599 font size. The open tag always pushes a style stack entry. The close tag
 600 always pops the top item off the style stack.
 601 <BR>Attributes:
 602 <UL><B>SIZE</B>=[+ int | - int | int ]&nbsp; [clamped: >=1 &amp;&amp; &lt;=
 603 7]
 604 <BR><B>POINT-SIZE=</B>[+ int | - int | int ] [clamped: >= 1 &amp;&amp;
 605 &lt;= 1600]
 606 <BR><B>FONT-WEIGHT</B>=[+ int | - int | int ] [clamped: >= 100 &amp;&amp;
 607 &lt;= 900]
 608 <BR><B>COLOR</B>=colorspec
 609 <BR><B>FACE</B>=string</UL>
 610 </UL>
 611 A note regarding the style stack: The pop of the stack checks to see if
 612 the top of the stack is an ANCHOR tag. If it is not an anchor then the
 613 top item is unconditionally popped. If the top of the style stack is an
 614 anchor tag then the code searches for either the bottom of the stack or
 615 the first style stack entry not created by an anchor tag. If the entry
 616 is followed by another entry then the entry is removed from the stack (an
 617 out-of-order pop in other words). In this case the anchor style stack entry
 618 is left untouched.
 619 <H3>
 620
 621 <HR ALIGN=LEFT WIDTH="50%"></H3>
 622 <B>text, entities</B>
 623 <UL>These are basic content objects that get fed directly to the output.
 624 In navigator the text is processed by doing line-breaking (entities have
 625 been converted to text already by the parser). The line-breaking is controlled
 626 by the margin settings and the list depth, the floating elements, the style
 627 attributes (font size, etc.), the preformatted flag, the no-break flag
 628 and so on.</UL>
 629 <B>IMG, IMAGE</B>
 630 <UL>Close tag is ignored.
 631 <BR>Attributes:
 632 <UL><B>ISMAP</B>
 633 <BR><B>USEMAP</B>=url
 634 <BR><B>ALIGN</B>=alignparam
 635 <BR><B>SRC</B>=url [ whitespace is stripped ]
 636 <BR><B>LOWSRC</B>=url
 637 <BR><B>ALT</B>=string
 638 <BR><B>WIDTH</B>=value-or-pct (pct of <TT>right-left</TT> width)
 639 <BR><B>HEIGHT</B>=value-or-pct (pct of window height)
 640 <BR><B>BORDER</B>=int [clamped: >= 0]
 641 <BR><B>VSPACE</B>=int [clamped: >= 0]
 642 <BR><B>HSPACE</B>=int [clamped: >= 0]
 643 <BR><B>SUPPRESS</B>=true | false (only in blocked image layout???)</UL>
 644 </UL>
 645 <B>HR</B>
 646 <UL>Closes the paragraph. If an open tag then does a conditional soft line
 647 break. The rule inherits alignment from the parent container unless there
 648 is no container (then it's centered) or if the tag defines it's own alignment.
 649 After the object is inserted into the layout stream a soft line break is
 650 inserted as well.
 651 <BR>Attributes:
 652 <UL><B>ALIGN</B>=divalign (sort of; in laytags.c it's divalign; in layhrule.c
 653 it's left or right only)
 654 <BR><B>SIZE</B>=int (1 to 100 inclusive)
 655 <BR><B>WIDTH</B>=val-or-pct (pct of <TT>right-left</TT> width)
 656 <BR><B>NOSHADE</B></UL>
 657 </UL>
 658 <B>BR</B>
 659 <UL>Does an unconditional soft break. If clear is set then it will also
 660 soft break until either the left or right or both margins are clear of
 661 floating elements. Note that<FONT COLOR="#0000FF"> /BR == BR!</FONT>
 662 <BR>Attributes:
 663 <UL><B>CLEAR</B>=left | right | all | both</UL>
 664 </UL>
 665 <B>WBR</B>
 666 <UL>Soft word break.
 667 <BR>Attributes: none</UL>
 668 <B>EMBED</B>
 669 <UL>Close tag does nothing. Embed's operate inline just like images (they
 670 don't close the paragraph).
 671 <BR>Attributes:
 672 <UL><B>HIDDEN</B>=no | false | off
 673 <BR><B>ALIGN</B>=alignparam
 674 <BR><B>SRC</B>=url
 675 <BR><B>WIDTH</B>=val-or-pct (pct of <TT>right-left</TT> width)
 676 <BR><B>HEIGHT</B>=val-of-pct; if val is &lt; 1 (sometimes) the element
 677 gets HIDDEN automatically
 678 <BR><B>BORDER</B>=int (unsupported by navigator)
 679 <BR><B>VSPACE</B>=int [clamped: >= 0]
 680 <BR><B>HSPACE</B>=int [clamped: >= 0]</UL>
 681 </UL>
 682 <B>NOEBMED</B>
 683 <UL>Used when EMBED's are disabled. It is a container for regular content
 684 that has no stylistic consequences (no line breaking, no style stack effect,
 685 etc.).</UL>
 686 <B>APPLET</B>
 687 <UL>Applet tags don't nest (there is a notion of current_applet). The open
 688 tag automatically closes an open applet tag.
 689 <BR>Attributes:
 690 <UL><B>ALIGN</B>=alignparam
 691 <BR><B>CODE</B>=string
 692 <BR><B>CODEBASE</B>=string
 693 <BR><B>ARCHIVE</B>=string
 694 <BR><B>MAYSCRIPT</B>
 695 <BR><B>NAME</B>=string [clamped: white space is stripped out]
 696 <BR><B>WIDTH</B>=value-or-pct [pct of right-left width; clamped: >= 1]
 697 <BR><B>HEIGHT</B>=value-or-pct [pct of window height; clamped >= 1]
 698 <BR><B>BORDER</B>=int [clamped: >= 0]
 699 <BR><B>HSPACE</B>=int [clamped: >= 0]
 700 <BR><B>VSPACE</B>=int [clamped: >= 0]</UL>
 701 If no width is provided:
 702 <UL>if a height was provided, use the height. Otherwise, use 90% of the
 703 window width if percentage widths are allowed, otherwise use a value of
 704 600.
 705 <BR>&nbsp;</UL>
 706 If no height is provided:
 707 <UL>if a width was provided, use the width. Otherwise, use 50% of the window
 708 height if percentage widths are allowed, otherwise use a value of 400.</UL>
 709 If the applet is hidden, then the widht/height get forced to zero.</UL>
 710 <B>PARAM</B>
 711 <UL>The param tag is supported when contained by the APPLET tag or the
 712 OBJECT tag. It has no stylistic consequences. The attribute values from
 713 the tag are passed to the containing APPLET or OBJECT. Note that <FONT COLOR="#0000FF">/PARAM
 714 == PARAM</FONT>.
 715 <BR>Attributes:
 716 <UL><B>NAME</B>=string [clamped: white space is stripped out]
 717 <BR><B>VALUE</B>=string [clamped: white space is stripped out]</UL>
 718 White space being stripped is done as follows: leading and trailing whitespace
 719 is removed. Any embedded whitespace is left alone except if it's a non-space
 720 whitespace in which case it is removed.</UL>
 721 <B>OBJECT</B>
 722 <UL>The open tag pushes an object onto the object stack. The close tag
 723 pops from the object stack. I don't understand how the data stuff works.
 724 <BR>Attributes:
 725 <UL><B>CLASSID</B>=string (clsid:, java:, javaprogram:, javabean: are the
 726 supported prefixes; maybe it's a url if no prefix shown?)
 727 <BR><B>TYPE</B>=string (a mime type)
 728 <BR><B>DATA</B>=string (data: prefix mentions a url)</UL>
 729 There are more attributes that depend on the type of object being embedded
 730 in the page. If the object is a java bean (?) then the applet parameters
 731 are supported:
 732 <UL>CLASSID
 733 <BR>HIDDEN
 734 <BR>ALIGN
 735 <BR>CLASSID (instead of CODE)
 736 <BR>CODEBASE
 737 <BR>ARCHIVE
 738 <BR>MAYSCRIPT
 739 <BR>ID (applets use NAME)
 740 <BR>WIDTH
 741 <BR>HEIGHT
 742 <BR>BORDER
 743 <BR>HSPACE
 744 <BR>VSPACE</UL>
 745 </UL>
 746 <B>MAP</B>
 747 <UL>The open tag automatically closes an open map (maps don't nest). There
 748 is no stylistic consequence of the map nor does it provide any visible
 749 presentation in the normal layout case (an editor would do something different).
 750 The map can be declared anywhere in the document.
 751 <BR>Attributes:
 752 <UL><B>NAME</B>=string [clamped: white space is stripped out]</UL>
 753 </UL>
 754 <B>AREA</B>
 755 <UL>Does nothing if there is no current map or the tag is a close tag.
 756 <BR>Attributes:
 757 <UL><B>SHAPE</B>=default | rect | circle | poly | polygon
 758 <BR><B>ALT</B>=string [clamped: newlines are stripped]
 759 <BR><B>COORDS</B>=coord-list
 760 <BR><B>HREF=</B>url
 761 <UL><B>TARGET</B>=target (only if HREF is specified)</UL>
 762 <B>SUPPRESS</B></UL>
 763 </UL>
 764 <B>SERVER</B>
 765 <UL>A container for server-side javascript. Not evaluated by the client
 766 (parsed and ignored). Note: The navigator parser doesn't expand entities
 767 in a <B>SERVER </B>tag.</UL>
 768 <B>SPACER</B>
 769 <UL>Close tag is ignored. Open tag provides whitespace during layout: <B>TYPE</B>=line/vert/vertical
 770 causes a conditional soft line break and then adds <B>SIZE </B>to the Y
 771 layout coordinate. <B>TYPE</B>=word causes a conditional soft word break
 772 and then adds <B>SIZE </B>to the X layout coordinate. <B>TYPE</B>=block
 773 causes <FONT COLOR="#DD0000">blockish </FONT>layout stuff to happen.
 774 <BR>Attributes:
 775 <UL><B>TYPE</B>=line | vert | vertical | block (default: word)
 776 <UL><B>ALIGN</B>=alignparam (these 3 params are only for <B>TYPE</B>=block)
 777 <BR><B>WIDTH</B>=value-or-pct
 778 <BR><B>HEIGHT</B>=value-or-pct</UL>
 779 <B>SIZE</B>=int [clampled: >= 0]</UL>
 780 </UL>
 781
 782 <H3>
 783
 784 <HR ALIGN=LEFT WIDTH="50%"></H3>
 785 <B>SCRIPT</B>
 786 <UL>Note: The navigator parser doesn't expand entities in a SCRIPT tag.
 787 <BR>Attributes:
 788 <UL><B>LANGUAGE</B>=LiveScript | Mocha | JavaScript1.1 | JavaScript1.2
 789 <BR><B>TYPE</B>="text/javascript" | "text/css"
 790 <BR><B>HREF</B>=url
 791 <BR><B>ARCHIVE</B>=url
 792 <BR><B>CODEBASE</B>=url
 793 <BR><B>ID</B>=string
 794 <BR><B>SRC</B>=url</UL>
 795 </UL>
 796 <B>NOSCRIPT</B>
 797 <UL>Used when scripting is off or by backrev browsers. It is a container
 798 that has no stylistic consequences.</UL>
 799
 800 <H3>
 801
 802 <HR ALIGN=LEFT WIDTH="50%"></H3>
 803 <B>FORM&nbsp;</B>
 804 <UL>Attributes:
 805 <UL><B>ACTION</B>=href
 806 <BR><B>ENCODING</B>=string
 807 <BR><B>TARGET</B>=string
 808 <BR><B>METHOD</B>=get | post</UL>
 809 </UL>
 810 <B>ISINDEX&nbsp;</B>
 811 <UL>This tag is a shortcut for creating a form element with a submit button
 812 and a single text field. If the PROMPT attribute is not present in the
 813 tag then the value used is <B>"This is a searchable index. Enter search
 814 keywords:"</B>.
 815
 816 <P>Attributes:
 817 <UL><B>PROMPT</B>=string
 818 <BR><B>ACTION</B>=href
 819 <BR><B>ENCODING</B>=string
 820 <BR><B>TARGET</B>=string
 821 <BR><B>METHOD</B>=get | post</UL>
 822 </UL>
 823 <B>INPUT&nbsp;</B>
 824 <UL>Attributes vary according to type:
 825 <UL><B>TYPE</B>= text | radio | checkbox | hidden | submit | reset | password
 826 | button | image | file | jot | readonly | object
 827 <BR><B>NAME</B>= string
 828 <BR>&nbsp;</UL>
 829 <B>TYPE</B>=image
 830 <UL>attributes are from the IMG tag (!)</UL>
 831 <B>TYPE</B>= text | password | file
 832 <UL>font style is forced to fixed
 833 <BR><B>VALUE</B>= string
 834 <BR><B>SIZE</B>= int (clamped; >= 1)
 835 <BR><B>MAXLENGTH</B>= int (not clamped!)</UL>
 836 <B>TYPE</B>= submit | reset | button | hidden | readonly
 837 <UL><B>VALUE</B>=string; default if no value to the attribute varies according
 838 to the type:
 839 <UL><B>submit</B> -> "Submit Query"
 840 <BR><B>reset</B> -> "Reset"
 841 <BR>others -> "&nbsp; " (2 spaces)
 842 <BR>Note also that the value has newlines stripped from it</UL>
 843 <B>WIDTH</B>=int (clamped >=0 &amp;&amp; &lt;= 1000) (only for submit,
 844 reset or button)
 845 <BR><B>HEIGHT</B>=int (clamped >=0 &amp;&amp; &lt;= 1000) (only for submit,
 846 reset or button)</UL>
 847 <B>TYPE</B>=radio | checkbox
 848 <UL><B>CHECKED</B> (flag - if present then set to true)
 849 <BR><B>VALUE</B>= string (the default value is "on")</UL>
 850 </UL>
 851 <B>SELECT&nbsp;</B>
 852 <UL>Attributes:
 853 <UL><B>MULTIPLE</B> (boolean)
 854 <BR><B>SIZE</B>= int (clamped >= 1)
 855 <BR><B>NAME=</B> string
 856 <BR><B>WIDTH</B>= int (clampled >= 0 &amp;&amp; &lt;= 1000)
 857 <BR><B>HEIGHT</B>= int (clamped >= 0 &amp;&amp; &lt;= 1000; only examined
 858 for single entry lists (!multiple || size==1))</UL>
 859 </UL>
 860 <B>OPTION&nbsp;</B>
 861 <UL>Lives inside the SELECT tag (ignored otherwise).
 862 <BR>Attributes:
 863 <UL><B>VALUE</B>=string
 864 <BR><B>SELECTED</B> boolean</UL>
 865 </UL>
 866 <B>TEXTAREA&nbsp;</B>
 867 <UL>Attributes:
 868 <UL><B>NAME</B>=string
 869 <BR><B>ROWS</B>=int (clamped; >= 1)
 870 <BR><B>COLS</B>=int (clamped; >= 1)
 871 <BR><B>WRAP</B>= off | hard | soft (default is off; any value which is
 872 not known turns into soft)</UL>
 873 </UL>
 874 <B>KEYGEN&nbsp;</B>
 875 <UL>Attributes:
 876 <UL><B>NAME</B>=string
 877 <BR><B>CHALLENGE</B>=string
 878 <BR><B>PQG</B>=string
 879 <BR><B>KEYTYPE</B>=string</UL>
 880 </UL>
 881
 882 <H3>
 883
 884 <HR ALIGN=LEFT WIDTH="50%"></H3>
 885 <B>BASEFONT&nbsp;</B>
 886 <UL>Sets the base font value which +/- size values in FONT tags are relative
 887 to.
 888 <BR>Attributes:
 889 <UL>SIZE=+ int | - int | int (just like FONT)</UL>
 890 </UL>
 891
 892 <H2>
 893
 894 <HR WIDTH="100%">Unsupported</H2>
 895 <B>NSCP_CLOSE, NSCP_OPEN, NSCP_REBLOCK, MQUOTE, CELL, SUBDOC, CERTIFICATE,
 896 INLINEINPUTTHICK, INLINEINPUTDOTTED, COLORMAP, HYPE, SPELL, NSDT</B>
 897 <UL>These tags are unsupported because they are used internally by netscape
 898 and are never seen in real content. If somebody does use them between 4.0
 899 and magellan, tough beans. We never documented them so they lose.</UL>
 900
 901 </BODY>
 902 </HTML>