<!ELEMENT BODY O O (%block;|SCRIPT)+ +(INS|DEL) -- document body -->
<!ATTLIST BODY
  %attrs;                     -- %coreattrs, %i18n, %events --
  onload   %Script; -sharpIMPLIED  -- the document has been loaded --
  onunload %Script; -sharpIMPLIED  -- the document has been removed --
>

this is the DTD code I saw in http://www.w3.org/TR/html4/st..

however, I find it a little different from the DTD I"m learning right now. Is it an early DTD standard? If so, can you send a technical document of this standard?

here are the differences I found

1. ELEMENT

   //ELEMENT
   <!ELEMENT  (|)+>
   
   
   
   //http://www.w3.org/TR/html4/strict.dtd
   <!ELEMENT BODY O O (%block;|SCRIPT)+ +(INS|DEL) -- document body -->

   • what do those two O mean?
   • where -- document body-- is a comment?
   How can + (INS | DEL) be added to
   • ?

2. ATTLIST

   //ATTLIST
   <!ATTLIST     >
   
   
   
   //http://www.w3.org/TR/html4/strict.dtd
   <!ATTLIST BODY
     %attrs;                     -- %coreattrs, %i18n, %events --
     onload   %Script; -sharpIMPLIED  -- the document has been loaded --
     onunload %Script; -sharpIMPLIED  -- the document has been removed --
   >

   • can multiple attribute names be written in a ATTLIST ?