<A>（リンク： Anchor ）

HTML1.0

<!ELEMENT A     - -  (%text)>
<!ATTLIST A
        %linkattributes;
        >

HTML2.0

<!ENTITY % A.content   "(%heading|%text)*">

<!ELEMENT A     - - %A.content -(A)>
<!ATTLIST A
        HREF CDATA #IMPLIED
        NAME CDATA #IMPLIED
        %linkExtraAttributes;
        %SDAPREF; "<Anchor: #AttList>"
        >
<!-- <A>                Anchor; source/destination of link      -->
<!-- <A NAME="...">     Name of this anchor                     -->
<!-- <A HREF="...">     Address of link destination             -->
<!-- <A URN="...">      Permanent address of destination        -->
<!-- <A REL=...>        Relationship to destination             -->
<!-- <A REV=...>        Relationship of destination to this     -->
<!-- <A TITLE="...">    Title of destination (advisory)         -->
<!-- <A METHODS="...">  Operations on destination (advisory)    -->

HTML2.x

   <!ENTITY % A.content   "(%heading|%text)*">

   <!ELEMENT A     - - %A.content -(A)>
   <!ATTLIST A
           %attrs;
           HREF CDATA #IMPLIED
           NAME CDATA #IMPLIED
           %linkExtraAttributes;
           %SDAPREF; "<Anchor: #AttList>"
           >
   <!-- <A>       Anchor; source/destination of link -->
   <!-- <A NAME="..."> Name of this anchor           -->
   <!-- <A HREF="..."> Address of link destination        -->
   <!-- <A URN="...">  Permanent address of destination   -->
   <!-- <A REL=...>    Relationship to destination        -->
   <!-- <A REV=...>    Relationship of destination to this     -->
   <!-- <A TITLE="...">     Title of destination (advisory)         -->
   <!-- <A METHODS="...">   Operations on destination (advisory)    -->
   <!-- <A CHARSET="...">   Charset of destination (advisory)  -->
   <!-- <A LANG="...">     Language of contents btw <A> and </A>   -->
   <!-- <A DIR=...>        Contents is a new counterflow embedding -->

HTML+

<!ELEMENT A - - (#PCDATA | IMG | EM | EMBED)*>
<!ATTLIST A
        id      ID      #IMPLIED -- as target of link --
        name    CDATA   #IMPLIED -- for backwards compatibility with HTML--
        shape   CDATA   #IMPLIED -- list of points for shaped buttons --
        href    %URL;   #IMPLIED -- destination node --
        rel     CDATA   #IMPLIED -- forward relationship type --
        rev     CDATA   #IMPLIED -- reverse relationship type --
        methods CDATA   #IMPLIED -- supported public methods --
        effect  CDATA   #IMPLIED -- replace/new/overlay/embed --
        print   CDATA   #IMPLIED -- reference/footnote/section --
        title   CDATA   #IMPLIED -- when otherwise unavailable --
        type    CDATA   #IMPLIED -- for presentation cues --
        size    NAMES   #IMPLIED -- for progress cues --
        lang    CDATA   #IMPLIED -- ISO language abbreviation -->
<!-- Other kinds of relationships between documents -->

HTML3.0

<!ENTITY % linkExtraAttributes -- URN moved to %url.link --
       "rel %linkType #IMPLIED -- forward relationship type --
        rev %linkType #IMPLIED -- reversed relationship type
                                  to referent data --
        title   CDATA #IMPLIED -- advisory only --
        methods NAMES #IMPLIED -- supported public methods of the object:
                                        TEXTSEARCH, GET, HEAD, ... --
        ">

<![ %HTML.Deprecated [
    <!ENTITY % A.content "(%heading|%text)+">
]]>

<!ENTITY % A.content   "(%text)+">

<!ELEMENT A     - - %A.content -(A)>

<!ATTLIST A
        %attrs;
        href   %URI;  #IMPLIED
        %url.link;    -- standard link attributes --
        %linkName;     -- name attribute is deprecated; use ID instead --
        shape %SHAPE; #IMPLIED -- for shaped hotzones in FIGs --
        %linkExtraAttributes;
        >

HTML3.2

<!ELEMENT A - - (%text)* -(A)>
<!ATTLIST A
        name    CDATA   #IMPLIED    -- named link end --
        href    %URL    #IMPLIED    -- URL for linked resource --
        rel     CDATA   #IMPLIED    -- forward link types --
        rev     CDATA   #IMPLIED    -- reverse link types --
        title   CDATA   #IMPLIED    -- advisory title string --
        >

HTML 4.0 Mobile

<!ENTITY % Shape "(rect|circle|poly|default)">
<!ENTITY % Coords "CDATA" -- comma separated list of lengths -->

<![ %HTML.Strict; [
<!ELEMENT A - - (%inline;)* -(A)       -- anchor -->
<!ATTLIST A
  %attrs;                              -- %coreattrs, %i18n, %events --
  charset     %Charset;      #IMPLIED  -- char encoding of linked resource --
  type        %ContentType;  #IMPLIED  -- advisory content type --
  name        CDATA          #IMPLIED  -- named link end --
  href        %URI;          #IMPLIED  -- URI for linked resource --
  hreflang    %LanguageCode; #IMPLIED  -- language code --
  rel         %LinkTypes;    #IMPLIED  -- forward link types --
  rev         %LinkTypes;    #IMPLIED  -- reverse link types --
  accesskey   %Character;    #IMPLIED  -- accessibility key character --
  shape       %Shape;        rect      -- for use with client-side image maps --
  coords      %Coords;       #IMPLIED  -- for use with client-side image maps --
  tabindex    NUMBER         #IMPLIED  -- position in tabbing order --
  onfocus     %Script;       #IMPLIED  -- the element got the focus --
  onblur      %Script;       #IMPLIED  -- the element lost the focus --
  >
]]>

<![ %HTML.Mobile; [
<!ELEMENT A - - (%inline;)* -(A)       -- anchor -->
<!ATTLIST A
  %attrs;                              -- %coreattrs, %i18n --
  charset     %Charset;      #IMPLIED  -- char encoding of linked resource --
  type        %ContentType;  #IMPLIED  -- advisory content type --
  name        CDATA          #IMPLIED  -- named link end --
  href        %URI;          #IMPLIED  -- URI for linked resource --
  hreflang    %LanguageCode; #IMPLIED  -- language code --
  rel         %LinkTypes;    #IMPLIED  -- forward link types --
  rev         %LinkTypes;    #IMPLIED  -- reverse link types --
  accesskey   %Character;    #IMPLIED  -- accessibility key character --
  tabindex    NUMBER         #IMPLIED  -- position in tabbing order --
  >
]]>

HTML 4.01 Strict

<!ENTITY % Shape "(rect|circle|poly|default)">
<!ENTITY % Coords "CDATA" -- comma-separated list of lengths -->

<!ELEMENT A - - (%inline;)* -(A)       -- anchor -->
<!ATTLIST A
  %attrs;                              -- %coreattrs, %i18n, %events --
  charset     %Charset;      #IMPLIED  -- char encoding of linked resource --
  type        %ContentType;  #IMPLIED  -- advisory content type --
  name        CDATA          #IMPLIED  -- named link end --
  href        %URI;          #IMPLIED  -- URI for linked resource --
  hreflang    %LanguageCode; #IMPLIED  -- language code --
  rel         %LinkTypes;    #IMPLIED  -- forward link types --
  rev         %LinkTypes;    #IMPLIED  -- reverse link types --
  accesskey   %Character;    #IMPLIED  -- accessibility key character --
  shape       %Shape;        rect      -- for use with client-side image maps --
  coords      %Coords;       #IMPLIED  -- for use with client-side image maps --
  tabindex    NUMBER         #IMPLIED  -- position in tabbing order --
  onfocus     %Script;       #IMPLIED  -- the element got the focus --
  onblur      %Script;       #IMPLIED  -- the element lost the focus --
  >

HTML 4.01 Transitional

<!ENTITY % Shape "(rect|circle|poly|default)">
<!ENTITY % Coords "CDATA" -- comma-separated list of lengths -->

<!ELEMENT A - - (%inline;)* -(A)       -- anchor -->
<!ATTLIST A
  %attrs;                              -- %coreattrs, %i18n, %events --
  charset     %Charset;      #IMPLIED  -- char encoding of linked resource --
  type        %ContentType;  #IMPLIED  -- advisory content type --
  name        CDATA          #IMPLIED  -- named link end --
  href        %URI;          #IMPLIED  -- URI for linked resource --
  hreflang    %LanguageCode; #IMPLIED  -- language code --
  target      %FrameTarget;  #IMPLIED  -- render in this frame --
  rel         %LinkTypes;    #IMPLIED  -- forward link types --
  rev         %LinkTypes;    #IMPLIED  -- reverse link types --
  accesskey   %Character;    #IMPLIED  -- accessibility key character --
  shape       %Shape;        rect      -- for use with client-side image maps --
  coords      %Coords;       #IMPLIED  -- for use with client-side image maps --
  tabindex    NUMBER         #IMPLIED  -- position in tabbing order --
  onfocus     %Script;       #IMPLIED  -- the element got the focus --
  onblur      %Script;       #IMPLIED  -- the element lost the focus --
  >

HTML 4.01 Frameset

<!ENTITY % Shape "(rect|circle|poly|default)">
<!ENTITY % Coords "CDATA" -- comma-separated list of lengths -->

<!ELEMENT A - - (%inline;)* -(A)       -- anchor -->
<!ATTLIST A
  %attrs;                              -- %coreattrs, %i18n, %events --
  charset     %Charset;      #IMPLIED  -- char encoding of linked resource --
  type        %ContentType;  #IMPLIED  -- advisory content type --
  name        CDATA          #IMPLIED  -- named link end --
  href        %URI;          #IMPLIED  -- URI for linked resource --
  hreflang    %LanguageCode; #IMPLIED  -- language code --
  target      %FrameTarget;  #IMPLIED  -- render in this frame --
  rel         %LinkTypes;    #IMPLIED  -- forward link types --
  rev         %LinkTypes;    #IMPLIED  -- reverse link types --
  accesskey   %Character;    #IMPLIED  -- accessibility key character --
  shape       %Shape;        rect      -- for use with client-side image maps --
  coords      %Coords;       #IMPLIED  -- for use with client-side image maps --
  tabindex    NUMBER         #IMPLIED  -- position in tabbing order --
  onfocus     %Script;       #IMPLIED  -- the element got the focus --
  onblur      %Script;       #IMPLIED  -- the element lost the focus --
  >

ISO/IEC 15445(ISO-HTML)

<!ELEMENT A           - -  (%text;)* -(A) >

<!ATTLIST A
  --Case shall not be taken into account when determining a match
    between an ID value and a NAME value, between an ID value and 
    an HREF value or between a NAME value and an HREF value.  
    Comparisons should be made with the values folded to upper case.

    The NAME attribute value specification shall be processed as if the
    declared value were NAME.

    It is recommended that authors of HTML documents specify both ID
    and NAME attributes, and use values restricted to the 40 characters
    "ABCDEFGHIJKLMNOPQRSTUVWXYZ.-_:0123456789".  When both attributes
    are specified, they shall have identical values.

    COORDS shall not be specified if SHAPE has the value `default'.
  --
    %core;                         -- Element CLASS, ID and TITLE --
    %i18n;                         -- Internationalization DIR and LANG --
    ACCESSKEY  CDATA      #IMPLIED -- Accessibility key character --
    CHARSET    CDATA      #IMPLIED -- Character encoding as per RFC2045 --
    COORDS     CDATA      #IMPLIED -- Comma separated list of values --
    HREF       %URI;      #IMPLIED -- Source anchor is URI of target --
    HREFLANG   NAME       #IMPLIED -- Language code of resource --
    NAME       CDATA      #IMPLIED -- Target anchor --
    REL        CDATA      #IMPLIED -- Forward link types --
    REV        CDATA      #IMPLIED -- Reverse link types --
    SHAPE      %shape;        rect -- Control interpretation of coords --
    TABINDEX   NUMBER     #IMPLIED -- Position in tabbing order --
    TYPE       CDATA      #IMPLIED -- Advisory content type -->

XHTML 1.0 Strict

<!-- content is %Inline; except that anchors shouldn't be nested -->

<!ELEMENT a %a.content;>
<!ATTLIST a
  %attrs;
  %focus;
  charset     %Charset;      #IMPLIED
  type        %ContentType;  #IMPLIED
  name        NMTOKEN        #IMPLIED
  href        %URI;          #IMPLIED
  hreflang    %LanguageCode; #IMPLIED
  rel         %LinkTypes;    #IMPLIED
  rev         %LinkTypes;    #IMPLIED
  shape       %Shape;        "rect"
  coords      %Coords;       #IMPLIED
  >

XHTML 1.0 Transitional

<!-- content is %Inline; except that anchors shouldn't be nested -->

<!ELEMENT a %a.content;>
<!ATTLIST a
  %attrs;
  %focus;
  charset     %Charset;      #IMPLIED
  type        %ContentType;  #IMPLIED
  name        NMTOKEN        #IMPLIED
  href        %URI;          #IMPLIED
  hreflang    %LanguageCode; #IMPLIED
  rel         %LinkTypes;    #IMPLIED
  rev         %LinkTypes;    #IMPLIED
  shape       %Shape;        "rect"
  coords      %Coords;       #IMPLIED
  target      %FrameTarget;  #IMPLIED
  >

XHTML 1.0 Frameset

<!-- content is %Inline; except that anchors shouldn't be nested -->

<!ELEMENT a %a.content;>
<!ATTLIST a
  %attrs;
  %focus;
  charset     %Charset;      #IMPLIED
  type        %ContentType;  #IMPLIED
  name        NMTOKEN        #IMPLIED
  href        %URI;          #IMPLIED
  hreflang    %LanguageCode; #IMPLIED
  rel         %LinkTypes;    #IMPLIED
  rev         %LinkTypes;    #IMPLIED
  shape       %Shape;        "rect"
  coords      %Coords;       #IMPLIED
  target      %FrameTarget;  #IMPLIED
  >

XHTML 1.1

<!ENTITY % a.element  "INCLUDE" >
<![%a.element;[
<!ENTITY % a.content
     "( #PCDATA | %InlNoAnchor.mix; )*"
>
<!ENTITY % a.qname  "a" >
<!ELEMENT %a.qname;  %a.content; >
<!-- end of a.element -->]]>

<!ENTITY % a.attlist  "INCLUDE" >
<![%a.attlist;[
<!ATTLIST %a.qname;
      %Common.attrib;
      href         %URI.datatype;           #IMPLIED
      charset      %Charset.datatype;       #IMPLIED
      type         %ContentType.datatype;   #IMPLIED
      hreflang     %LanguageCode.datatype;  #IMPLIED
      rel          %LinkTypes.datatype;     #IMPLIED
      rev          %LinkTypes.datatype;     #IMPLIED
      accesskey    %Character.datatype;     #IMPLIED
      tabindex     %Number.datatype;        #IMPLIED
>
<!-- end of a.attlist -->]]>

XHTML Basic

<!ENTITY % a.element  "INCLUDE" >
<![%a.element;[
<!ENTITY % a.content
     "( #PCDATA | %InlNoAnchor.mix; )*"
>
<!ENTITY % a.qname  "a" >
<!ELEMENT %a.qname;  %a.content; >
<!-- end of a.element -->]]>

<!ENTITY % a.attlist  "INCLUDE" >
<![%a.attlist;[
<!ATTLIST %a.qname;
      %Common.attrib;
      href         %URI.datatype;           #IMPLIED
      charset      %Charset.datatype;       #IMPLIED
      type         %ContentType.datatype;   #IMPLIED
      hreflang     %LanguageCode.datatype;  #IMPLIED
      rel          %LinkTypes.datatype;     #IMPLIED
      rev          %LinkTypes.datatype;     #IMPLIED
      accesskey    %Character.datatype;     #IMPLIED
      tabindex     %Number.datatype;        #IMPLIED
>
<!-- end of a.attlist -->]]>

XHTML Mobile Profile

<!ENTITY % a.element  "INCLUDE" >
<![%a.element;[
<!ENTITY % a.content
     "( #PCDATA | %InlNoAnchor.mix; )*"
>
<!ENTITY % a.qname  "a" >
<!ELEMENT %a.qname;  %a.content; >
<!-- end of a.element -->]]>

<!ENTITY % a.attlist  "INCLUDE" >
<![%a.attlist;[
<!ATTLIST %a.qname;
      %Common.attrib;
      href         %URI.datatype;           #IMPLIED
      charset      %Charset.datatype;       #IMPLIED
      type         %ContentType.datatype;   #IMPLIED
      hreflang     %LanguageCode.datatype;  #IMPLIED
      rel          %LinkTypes.datatype;     #IMPLIED
      rev          %LinkTypes.datatype;     #IMPLIED
      accesskey    %Character.datatype;     #IMPLIED
      tabindex     %Number.datatype;        #IMPLIED
>
<!-- end of a.attlist -->]]>