term% ls -F
term% cat index.txt
HTML(2)                       System Calls Manual                      HTML(2)

       parsehtml,  printitems,  validitems, freeitems, freedocinfo, dimenkind,
       dimenspec, targetid, targetname, fromStr, toStr - HTML parser

       #include <u.h>
       #include <libc.h>
       #include <html.h>

       Item*  parsehtml(uchar* data, int datalen, Rune* src, int mtype,
              int chset, Docinfo** pdi)

       void   printitems(Item* items, char* msg)

       int    validitems(Item* items)

       void   freeitems(Item* items)

       void   freedocinfo(Docinfo* d)

       int    dimenkind(Dimen d)

       int    dimenspec(Dimen d)

       int    targetid(Rune* s)

       Rune*  targetname(int targid)

       uchar* fromStr(Rune* buf, int n, int chset)

       Rune*  toStr(uchar* buf, int n, int chset)

       This library implements a parser for HTML 4.0  documents.   The  parsed
       HTML  is  converted  into an intermediate representation that describes
       how the formatted HTML should be laid out.

       Parsehtml parses an entire HTML document contained in the  buffer  data
       and having length datalen.  The URL of the document should be passed in
       as src.  Mtype is the media type  of  the  document,  which  should  be
       either  TextHtml  or  TextPlain.   The character set of the document is
       described in chset, which can be one of US_Ascii, ISO_8859_1, UTF_8  or
       Unicode.   The  return  value  is  a  linked  list  of Item structures,
       described in detail below.  As a side effect, *pdi is set to point to a
       newly  created  Docinfo structure, containing information pertaining to
       the entire document.

       The library expects two allocation routines to be provided by the call‐
       er, emalloc and erealloc.  These routines are analogous to the standard
       malloc and realloc routines, except that they should not return if  the
       memory  allocation fails.  In addition, emalloc is required to zero the

       For debugging purposes, printitems may be called to  display  the  con‐
       tents  of  an  item  list; individual items may be printed using the %I
       print verb, installed on the first call to parsehtml.  validitems  tra‐
       verses  the item list, checking that all of the pointers are valid.  It
       returns 1 is everything is ok, and 0 if an error was found.   Normally,
       one  would  not  call  these  routines directly.  Instead, one sets the
       global variable dbgbuild and the library calls them automatically.  One
       can  also set warn, to cause the library to print a warning whenever it
       finds a problem with the input document, and dbglex, to print debugging
       information in the lexer.

       When  an item list is finished with, it should be freed with freeitems.
       Then, freedocinfo should be called on the pointer returned in *pdi.

       Dimenkind and dimenspec are provided to interpret the  Dimen  type,  as
       described in the section Dimension Specifications.

       Frame  target  names  are mapped to integer ids via a global, permanent
       mapping.  To find the value for a  given  name,  call  targetid,  which
       allocates  a new id if the name hasn't been seen before.  The name of a
       given, known id may be retrieved using targetname.  The library  prede‐
       fines FTtop, FTself, FTparent and FTblank.

       The  library handles all text as Unicode strings (type Rune*).  Charac‐
       ter set conversion is provided by fromStr and toStr.  FromStr  takes  n
       Unicode  characters  from  buf  and  converts them to the character set
       described by chset.  ToStr takes n  bytes  from  buf,  interpretted  as
       belonging  to  character  set  chset,  and  converts  them to a Unicode
       string.  Both routines null-terminate the result, and  use  emalloc  to
       allocate space for it.

       The  return  value of parsehtml is a linked list of variant structures,
       with the generic portion described by the following definition:

       typedef struct Item Item;
       struct Item
             Item*    next;
             int      width;
             int      height;
             int      ascent;
             int      anchorid;
             int      state;
             Genattr* genattr;
             int      tag;

       The field next points to the successor in the  linked  list  of  items,
       while  width,  height, and ascent are intended for use by the caller as
       part of the layout process.  Anchorid, if non-zero, gives  the  integer
       id  assigned by the parser to the anchor that this item is in (see sec‐
       tion Anchors).  State is a collection of flags and values described  as

             IFbrk =         0x80000000,
             IFbrksp =       0x40000000,
             IFnobrk =       0x20000000,
             IFcleft =       0x10000000,
             IFcright =      0x08000000,
             IFwrap =        0x04000000,
             IFhang =        0x02000000,
             IFrjust =       0x01000000,
             IFcjust =       0x00800000,
             IFsmap =        0x00400000,
             IFindentshift = 8,
             IFindentmask =  (255<<IFindentshift),
             IFhangmask =    255

       IFbrk  is  set  if  a  break  is to be forced before placing this item.
       IFbrksp is set if a 1 line space should be added to the break (in which
       case  IFbrk  is  also set).  IFnobrk is set if a break is not permitted
       before the item.  IFcleft is set if left floats should be cleared (that
       is,  if  the  list of pending left floats should be placed) before this
       item is placed, and IFcright is set for right floats.  In  both  cases,
       IFbrk  is  also set.  IFwrap is set if the line containing this item is
       allowed to wrap.  IFhang is set  if  this  item  hangs  into  the  left
       indent.   IFrjust  is  set  if  the line containing this item should be
       right justified, and IFcjust is set for center justified lines.  IFsmap
       is  used  to  indicate  that  an image is a server-side map.  The low 8
       bits, represented by IFhangmask, indicate the current  hang  into  left
       indent, in tenths of a tabstop.  The next 8 bits, represented by IFind‐
       entmask and IFindentshift, indicate the current indent in tab stops.

       The field genattr is an optional pointer  to  an  auxiliary  structure,
       described in the section Generic Attributes.

       Finally,  tag  describes which variant type this item has.  It can have
       one of the values Itexttag, Iruletag, Iimagetag, Iformfieldtag, Itable‐
       tag,  Ifloattag  or  Ispacertag.  For each of these values, there is an
       additional structure defined, which includes Item as an unnamed initial
       substructure, and then defines additional fields.

       Items  of  type Itexttag represent a piece of text, using the following

       struct Itext
             Rune* s;
             int   fnt;
             int   fg;
             uchar voff;
             uchar ul;

       Here s is a null-terminated Unicode string  of  the  actual  characters
       making up this text item, fnt is the font number (described in the sec‐
       tion Font Numbers), and fg is the RGB encoded color for the text.  Voff
       measures  the  vertical  offset from the baseline; subtract Voffbias to
       get the actual value (negative values represent a displacement down the
       page).   The  field  ul is the underline style: ULnone if no underline,
       ULunder for conventional underline, and ULmid for strike-through.

       Items of type Iruletag represent a horizontal rule, as follows:

       struct Irule
             uchar align;
             uchar noshade;
             int   size;
             Dimen wspec;

       Here align is the alignment specification (described in the correspond‐
       ing  section), noshade is set if the rule should not be shaded, size is
       the height of the rule (as set by the size attribute), and wspec is the
       desired width (see section Dimension Specifications).

       Items of type Iimagetag describe embedded images, for which the follow‐
       ing structure is defined:

       struct Iimage
             Rune*   imsrc;
             int     imwidth;
             int     imheight;
             Rune*   altrep;
             Map*    map;
             int     ctlid;
             uchar   align;
             uchar   hspace;
             uchar   vspace;
             uchar   border;
             Iimage* nextimage;

       Here imsrc is the URL of the image source,  imwidth  and  imheight,  if
       non-zero,  contain  the  specified  width and height for the image, and
       altrep is the text to use as an alternative to the image, if the  image
       is  not  displayed.   Map,  if set, points to a structure describing an
       associated client-side image map.  Ctlid is reserved  for  use  by  the
       application, for handling animated images.  Align encodes the alignment
       specification of the image.  Hspace contains the number  of  pixels  to
       pad  the  image  with  on either side, and Vspace the padding above and
       below.  Border is the width of the border to  draw  around  the  image.
       Nextimage  points  to  the next image in the document (the head of this
       list is Docinfo.images).

       For items of type Iformfieldtag, the following structure is defined:

       struct Iformfield
             Formfield* formfield;

       This adds a single  field,  formfield,  which  points  to  a  structure
       describing a field in a form, described in section Forms.

       For items of type Itabletag, the following structure is defined:

       struct Itable
             Table* table;

       Table points to a structure describing the table, described in the sec‐
       tion Tables.

       For items of type Ifloattag, the following structure is defined:

       struct Ifloat
             Item*   item;
             int     x;
             int     y;
             uchar   side;
             uchar   infloats;
             Ifloat* nextfloat;

       The item points to a single item (either a  table  or  an  image)  that
       floats  (the  text of the document flows around it), and side indicates
       the margin that this float sticks to; it is either ALleft  or  ALright.
       X  and  y  are reserved for use by the caller; these are typically used
       for the coordinates of the top of the float.  Infloats is used  by  the
       caller  to keep track of whether it has placed the float.  Nextfloat is
       used by the caller to link together all  of  the  floats  that  it  has

       For items of type Ispacertag, the following structure is defined:

       struct Ispacer
             int   spkind;

       Spkind  encodes  the  kind  of  spacer, and may be one of ISPnull (zero
       height and width), ISPvline (takes on height and ascent of the  current
       font),  ISPhspace  (has  the  width of a space in the current font) and
       ISPgeneral (for all other purposes, such as between markers and lists).

   Generic Attributes
       The genattr field of an item, if non-nil, points to  a  structure  that
       holds  the  values  of  attributes  not specific to any particular item
       type, as they occur on a wide variety of  underlying  HTML  tags.   The
       structure is as follows:

       typedef struct Genattr Genattr;
       struct Genattr
             Rune*   id;
             Rune*   class;
             Rune*   style;
             Rune*   title;
             SEvent* events;

       Fields id, class, style and title, when non-nil, contain values of cor‐
       respondingly named attributes of the  HTML  tag  associated  with  this
       item.   Events  is a linked list of events (with corresponding scripted
       actions) associated with the item:

       typedef struct SEvent SEvent;
       struct SEvent
             SEvent* next;
             int     type;
             Rune*   script;

       Here, next points to the next event in the list, type is one  of  SEon‐
       blur,  SEonchange,  SEonclick,  SEondblclick,  SEonfocus, SEonkeypress,
       SEonkeyup, SEonload, SEonmousedown, SEonmousemove, SEonmouseout,  SEon‐
       mouseover,  SEonmouseup,  SEonreset,  SEonselect, SEonsubmit or SEonun‐
       load, and script is the text of the associated script.

   Dimension Specifications
       Some structures include a dimension specification, used where a  number
       can  be followed by a % or a * to indicate percentage of total or rela‐
       tive weight.  This is encoded using the following structure:

       typedef struct Dimen Dimen;
       struct Dimen
             int kindspec;

       Separate kind and spec values are extracted using dimenkind and  dimen‐
       spec.   Dimenkind returns one of Dnone, Dpixels, Dpercent or Drelative.
       Dnone means that no dimension  was  specified.   In  all  other  cases,
       dimenspec  should  be called to find the absolute number of pixels, the
       percentage of total, or the relative weight.

   Background Specifications
       It is possible to set the background of the entire document,  and  also
       for  some  parts  of the document (such as tables).  This is encoded as

       typedef struct Background Background;
       struct Background
             Rune* image;
             int   color;

       Image, if non-nil, is the URL of an image to use as the background.  If
       this  is  nil, color is used instead, as the RGB value for a solid fill

   Alignment Specifications
       Certain items have alignment specifiers taken from the  following  enu‐
       merated type:

             ALnone = 0, ALleft, ALcenter, ALright, ALjustify,
             ALchar, ALtop, ALmiddle, ALbottom, ALbaseline

       These  values  correspond  to  the various alignment types named in the
       HTML 4.0 standard.  If an item has an alignment of ALleft  or  ALright,
       the library automatically encapsulates it inside a float item.

       Tables,  and  the  various  rows, columns and cells within them, have a
       more complex alignment specification, composed of separate vertical and
       horizontal alignments:

       typedef struct Align Align;
       struct Align
             uchar halign;
             uchar valign;

       Halign  can  be  one of ALnone, ALleft, ALcenter, ALright, ALjustify or
       ALchar.  Valign can be one of  ALnone,  ALmiddle,  ALbottom,  ALtop  or

   Font Numbers
       Text  items  have  an  associated font number (the fnt field), which is
       encoded as style*NumSize+size.  Here, style is one of FntR, FntI,  FntB
       or  FntT,  for  roman, italic, bold and typewriter font styles, respec‐
       tively, and size is Tiny, Small, Normal, Large or Verylarge.  The total
       number  of possible font numbers is NumFnt, and the default font number
       is DefFnt (which is roman style, normal size).

   Document Info
       Global information about an HTML page is stored in the following struc‐

       typedef struct Docinfo Docinfo;
       struct Docinfo
             // stuff from HTTP headers, doc head, and body tag
             Rune*       src;
             Rune*       base;
             Rune*       doctitle;
             Background  background;
             Iimage*     backgrounditem;
             int         text;
             int         link;
             int         vlink;
             int         alink;
             int         target;
             int         chset;
             int         mediatype;
             int         scripttype;
             int         hasscripts;
             Rune*       refresh;
             Kidinfo*    kidinfo;
             int         frameid;

             // info needed to respond to user actions
             Anchor*     anchors;
             DestAnchor* dests;
             Form*       forms;
             Table*      tables;
             Map*        maps;
             Iimage*     images;

       Src  gives  the URL of the original source of the document, and base is
       the base URL.  Doctitle is the document's title, as set  by  a  <title>
       element.  Background is as described in the section Background Specifi‐
       cations, and backgrounditem is set to be an image item  for  the  docu‐
       ment's  background  image (if given as a URL), or else nil.  Text gives
       the default foregound text color of the document,  link  the  unvisited
       hyperlink color, vlink the visited hyperlink color, and alink the color
       for highlighting hyperlinks (all in 24-bit RGB format).  Target is  the
       default  target frame id.  Chset and mediatype are as for the chset and
       mtype parameters to parsehtml.  Scripttype is the type of  any  scripts
       contained in the document, and is always TextJavascript.  Hasscripts is
       set if the document  contains  any  scripts.   Scripting  is  currently
       unsupported.   Refresh  is  the  contents of a <meta http-equiv=Refresh
       ...> tag, if any.  Kidinfo is set if this document is a  frameset  (see
       section Frames).  Frameid is this document's frame id.

       Anchors is a list of hyperlinks contained in the document, and dests is
       a list of hyperlink destinations within the  page  (see  the  following
       section  for details).  Forms, tables and maps are lists of the various
       forms, tables and  client-side  maps  contained  in  the  document,  as
       described  in  subsequent  sections.  Images is a list of all the image
       items in the document.

       The library builds two lists for all of the <a> elements (anchors) in a
       document.   Each anchor is assigned a unique anchor id within the docu‐
       ment.  For anchors which are hyperlinks (the href  attribute  was  sup‐
       plied), the following structure is defined:

       typedef struct Anchor Anchor;
       struct Anchor
             Anchor* next;
             int     index;
             Rune*   name;
             Rune*   href;
             int     target;

       Next  points  to  the next anchor in the list (the head of this list is
       Docinfo.anchors).  Index is the anchor id; each item within this hyper‐
       link  is  tagged  with this value in its anchorid field.  Name and href
       are the values of the correspondingly named attributes  of  the  anchor
       (in  particular, href is the URL to go to).  Target is the value of the
       target attribute (if provided) converted to a frame id.

       Destinations within the document (anchors with the name attribute  set)
       are held in the Docinfo.dests list, using the following structure:

       typedef struct DestAnchor DestAnchor;
       struct DestAnchor
             DestAnchor* next;
             int         index;
             Rune*       name;
             Item*       item;

       Next  is  the next element of the list, index is the anchor id, name is
       the value of the name attribute, and item is points to the item  within
       the parsed document that should be considered to be the destination.

       Any   forms   within   a  document  are  kept  in  a  list,  headed  by
       Docinfo.forms.  The elements of this list are as follows:

       typedef struct Form Form;
       struct Form
             Form*      next;
             int        formid;
             Rune*      name;
             Rune*      action;
             int        target;
             int        method;
             int        nfields;
             Formfield* fields;

       Next points to the next form in the list.  Formid is  a  serial  number
       for the form within the document.  Name is the value of the form's name
       or id attribute.  Action is the value of any action attribute.   Target
       is the value of the target attribute (if any) converted to a frame tar‐
       get id.  Method is one of HGet or HPost.   Nfields  is  the  number  of
       fields in the form, and fields is a linked list of the actual fields.

       The  individual  fields in a form are described by the following struc‐

       typedef struct Formfield Formfield;
       struct Formfield
             Formfield* next;
             int        ftype;
             int        fieldid;
             Form*      form;
             Rune*      name;
             Rune*      value;
             int        size;
             int        maxlength;
             int        rows;
             int        cols;
             uchar      flags;
             Option*    options;
             Item*      image;
             int        ctlid;
             SEvent*    events;

       Here, next points to the next field in the list.  Ftype is the type  of
       the  field,  which  can  be one of Ftext, Fpassword, Fcheckbox, Fradio,
       Fsubmit, Fhidden, Fimage, Freset, Ffile, Fbutton, Fselect or Ftextarea.
       Fieldid  is a serial number for the field within the form.  Form points
       back to the form containing this field.  Name, value, size,  maxlength,
       rows  and  cols  each contain the values of corresponding attributes of
       the field, if  present.   Flags  contains  per-field  flags,  of  which
       FFchecked and FFmultiple are defined.  Image is only used for fields of
       type Fimage; it points to an image item containing the image to be dis‐
       played.   Ctlid is reserved for use by the caller, typically to store a
       unique id of an associated control used to implement the field.  Events
       is  the same as the corresponding field of the generic attributes asso‐
       ciated with the item containing this field.  Options is  only  used  by
       fields  of type Fselect; it consists of a list of possible options that
       may be selected for that field, using the following structure:

       typedef struct Option Option;
       struct Option
             Option* next;
             int     selected;
             Rune*   value;
             Rune*   display;

       Next points to the next element of the list.  Selected is set  if  this
       option  is  to be displayed initially.  Value is the value to send when
       the form is submitted if this  option  is  selected.   Display  is  the
       string to display on the screen for this option.

       The  library builds a list of all the tables in the document, headed by
       Docinfo.tables.  Each element of this list has the following format:

       typedef struct Table Table;
       struct Table
             Table*       next;
             int          tableid;
             Tablerow*    rows;
             int          nrow;
             Tablecol*    cols;
             int          ncol;
             Tablecell*   cells;
             int          ncell;
             Tablecell*** grid;
             Align        align;
             Dimen        width;
             int          border;
             int          cellspacing;
             int          cellpadding;
             Background   background;
             Item*        caption;
             uchar        caption_place;
             Lay*         caption_lay;
             int          totw;
             int          toth;
             int          caph;
             int          availw;
             Token*       tabletok;
             uchar        flags;

       Next points to the next element in the list of tables.   Tableid  is  a
       serial  number  for the table within the document.  Rows is an array of
       row specifications (described below) and nrow is the number of elements
       in  this  array.  Similarly, cols is an array of column specifications,
       and ncol the size of this array.  Cells is a list of all  cells  within
       the  table  (structure described below) and ncell is the number of ele‐
       ments in this list.  Note that a cell may  span  multiple  rows  and/or
       columns,  thus  ncell  may  be  smaller than nrow*ncol.  Grid is a two-
       dimensional array of cells within the table; the cell at row i and col‐
       umn j is Table.grid[i][j].  A cell that spans multiple rows and/or col‐
       umns will be referenced by grid multiple times, however  it  will  only
       occur  once  in cells.  Align gives the alignment specification for the
       entire table, and width gives the requested width as a dimension speci‐
       fication.   Border,  cellspacing and cellpadding give the values of the
       corresponding attributes  for  the  table,  and  background  gives  the
       requested  background for the table.  Caption is a linked list of items
       to be displayed as the caption of the  table,  either  above  or  below
       depending  on  whether caption_place is ALtop or ALbottom.  Most of the
       remaining fields are reserved for use by the caller,  except  tabletok,
       which is reserved for internal use.  The type Lay is not defined by the
       library; the caller can provide its own definition.

       The Tablecol structure is defined for use by the caller.   The  library
       ensures  that the correct number of these is allocated, but leaves them
       blank.  The fields are as follows:

       typedef struct Tablecol Tablecol;
       struct Tablecol
             int   width;
             Align align;
             Point pos;

       The rows in the table are specified as follows:

       typedef struct Tablerow Tablerow;
       struct Tablerow
             Tablerow*  next;
             Tablecell* cells;
             int        height;
             int        ascent;
             Align      align;
             Background background;
             Point      pos;
             uchar      flags;

       Next is only used during parsing; it should be ignored by  the  caller.
       Cells  provides  a list of all the cells in a row, linked through their
       nextinrow fields (see below).  Height, ascent and pos are reserved  for
       use  by  the caller.  Align is the alignment specification for the row,
       and background is the background to use, if specified.  Flags  is  used
       by the parser; ignore this field.

       The individual cells of the table are described as follows:

       typedef struct Tablecell Tablecell;
       struct Tablecell
             Tablecell* next;
             Tablecell* nextinrow;
             int        cellid;
             Item*      content;
             Lay*       lay;
             int        rowspan;
             int        colspan;
             Align      align;
             uchar      flags;
             Dimen      wspec;
             int        hspec;
             Background background;
             int        minw;
             int        maxw;
             int        ascent;
             int        row;
             int        col;
             Point      pos;

       Next is used to link together the list of all cells within a table (Ta‐
       ble.cells), whereas nextinrow is used to link together  all  the  cells
       within  a single row (Tablerow.cells).  Cellid provides a serial number
       for the cell within the table.  Content is a linked list of  the  items
       to  be  laid  out  within  the  cell.   Lay is reserved for the user to
       describe how these items have been laid out.  Rowspan and  colspan  are
       the  number  of  rows  and  columns spanned by this cell, respectively.
       Align is the alignment specification for the cell.  Flags is some  com‐
       bination of TFparsing, TFnowrap and TFisth or'd together.  Here TFpars‐
       ing is used internally by the parser, and should be ignored.   TFnowrap
       means that the contents of the cell should not be wrapped if they don't
       fit the available width, rather, the table should be expanded  if  need
       be  (this  is set when the nowrap attribute is supplied).  TFisth means
       that the cell was created by the <th> element  (rather  than  the  <td>
       element),  indicating that it is a header cell rather than a data cell.
       Wspec provides a suggested width  as  a  dimension  specification,  and
       hspec  provides a suggested height in pixels.  Background gives a back‐
       ground specification for the individual cell.  Minw, maxw,  ascent  and
       pos are reserved for use by the caller during layout.  Row and col give
       the indices of the row and column of the top left-hand  corner  of  the
       cell within the table grid.

   Client-side Maps
       The  library builds a list of client-side maps, headed by Docinfo.maps,
       and having the following structure:

       typedef struct Map Map;
       struct Map
             Map*  next;
             Rune* name;
             Area* areas;

       Next points to the next element in the list, name is the  name  of  the
       map  (use  to  bind  it  to an image), and areas is a list of the areas
       within the image that comprise the map, using the following structure:

       typedef struct Area Area;
       struct Area
             Area*  next;
             int    shape;
             Rune*  href;
             int    target;
             Dimen* coords;
             int    ncoords;

       Next points to the next element in the  map's  list  of  areas.   Shape
       describes  the  shape  of  the  area, and is one of SHrect, SHcircle or
       SHpoly.  Href is the URL associated with this area in  its  role  as  a
       hypertext  link, and target is the target frame it should be loaded in.
       Coords is an array of coordinates for the shape,  and  ncoords  is  the
       size of this array (number of elements).

       If  the  Docinfo.kidinfo  field is set, the document is a frameset.  In
       this case, it is typical for parsehtml to return  nil,  as  a  document
       which  is  a  frameset should have no actual items that need to be laid
       out (such will appear only in subsidiary documents).   It  is  possible
       that  items will be returned by a malformed document; the caller should
       check for this and free any such items.

       The Kidinfo structure itself reflects the fact that  framesets  can  be
       nested within a document.  If is defined as follows:

       typedef struct Kidinfo Kidinfo;
       struct Kidinfo
             Kidinfo* next;
             int      isframeset;

             // fields for "frame"
             Rune*    src;
             Rune*    name;
             int      marginw;
             int      marginh;
             int      framebd;
             int      flags;

             // fields for "frameset"
             Dimen*   rows;
             int      nrows;
             Dimen*   cols;
             int      ncols;
             Kidinfo* kidinfos;
             Kidinfo* nextframeset;

       Next  is  only used if this structure is part of a containing frameset;
       it points to the next element in the list of children of that frameset.
       Isframeset  is set when this structure represents a frameset; if clear,
       it is an individual frame.

       Some fields are used only for framesets.  Rows is an array of dimension
       specifications  for  rows  in  the frameset, and nrows is the length of
       this array.  Cols is the corresponding array  for  columns,  of  length
       ncols.   Kidinfos  points to a list of components contained within this
       frameset, each of which may be a frameset or a frame.  Nextframeset  is
       only used during parsing, and should be ignored.

       The remaining fields are used if the structure describes a frame, not a
       frameset.  Src provides the URL for the document that  should  be  ini‐
       tially  loaded  into this frame.  Note that this may be a relative URL,
       in which case it should be interpretted using the containing document's
       URL  as the base.  Name gives the name of the frame, typically supplied
       via a name attribute in the HTML.  If no name was  given,  the  library
       allocates  one.   Marginw,  marginh  and  framebd are the values of the
       marginwidth, marginheight  and  frameborder  attributes,  respectively.
       Flags  can  contain  some combination of the following: FRnoresize (the
       frame had the noresize attribute  set,  and  the  user  should  not  be
       allowed to resize it), FRnoscroll (the frame should not have any scroll
       bars), FRhscroll (the frame  should  have  a  horizontal  scroll  bar),
       FRvscroll  (the frame should have a vertical scroll bar), FRhscrollauto
       (the frame should be automatically given a horizontal scroll bar if its
       contents  would not otherwise fit), and FRvscrollauto (the frame gets a
       vertical scrollbar only if required).



       W3C World Wide Web Consortium, ``HTML 4.01 Specification''.

       The entire HTML document must be loaded into memory before  any  of  it
       can be parsed.