2.1 titlesec

<..titlesec.4ht..>
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 % titlesec.4ht                          2014-07-12-22:36 %
 % Copyright (C) 2000--2009       Eitan M. Gurari         %
 <.TeX4ht copyright.>
 \ifx \ttl@assign@ii\:Undef
    \ifx \ttl@sect\:UnDef\else
      <.titlesec pre 2.3.5.>
    \fi
    \ifx \ttl@useclass\:UnDef\else
      <.titlesec since 2.3.5.>
    \fi
    <.shared titlesec.>
 \else
    <.titlesec 2005.>
 \fi
 \Hinput{titlesec}
 \endinput
 -_-_-

<..titlesec since 2.3.5..>
 \pend:defII\ttl@useclass{%
   \@ifstar {}{\SkipRefstepAnchor}}
 \let\ttl:select=\ttl@select
 \def\ttl@select#1{%
   \edef\sc:tp{\ifttl@label\else like\fi
              #1}\def\c:secnumdepth{\@nameuse{ttll@#1}}%
   \ttl:select{#1}}
 \let\ttl@write=\:gobbleII
 \let\ttl@glcmds\relax
 \let\ttl@beginlongest\@empty
 \let\ttl@midlongest\@empty
 \let\ttl@endlongest\@empty
 -_-_-

<..titlesec pre 2.3.5..>
 \pend:defII\ttl@sect{%
   \@ifstar {}{\SkipRefstepAnchor}}
 \let\ttl:select=\ttl@select
 \def\ttl@select#1#2#3#4#5{%
   \edef\sc:tp{\ifttl@label\else like\fi #1}\def\c:secnumdepth{#5}%
   \ttl:select{#1}{#2}{#3}{#4}{#5}}
 \let\ttl@write=\:gobbleIII
 -_-_-

<..shared titlesec..>
 \let\ttlh:hang=\ttlh@hang
 \def\ttlh@hang#1#2#3#4#5#6#7#8{%
    \HtmlEnv
    \expandafter\def\csname thetitle\sc:tp\endcsname{#2}%
    \csname no:\sc:tp\endcsname{#8}%
    \par \ttlh:hang{}{}{#3}{}{}{#6}{#7}{}}
 -_-_-

<..shared titlesec..>+
 \let\:seccntformat=\@seccntformat
 \def\@seccntformat#1{\ifnum 0=0\the\csname c@#1\endcsname\else
    \:seccntformat{#1}\fi}
 -_-_-

<..titlesec 2005..>
 \let\ttl:straight@i\ttl@straight@i
 \def\ttl@straight@i#1[#2]#3{%
   <.titlesec for nameref.>%
   \ifttl@label \else
      <.skip extra sec and subsec toc.>%
   \fi
   \edef\sc:tp{\ifttl@label\else like\fi #1}%
   \ttl:straight@i{#1}[#2]{#3}%
 }
 \def\ttlh@hang#1#2#3#4#5#6#7#8{%
    \def\c:secnumdepth{\@nameuse{ttll@\sc:tp}}%
    \:StartSec {\sc:tp}{%
          \ifttl@label \ifnum \c:secnumdepth >\c@secnumdepth
          \else \csname the\sc:tp\endcsname \fi \fi
        }{#8}%
 }
 \def\:tempc{%
    \let\ttl@savewrite\empty
    \o:ttl@select:
 }
 \HLet\ttl@select\:tempc
 -_-_-

<..skip extra sec and subsec toc..>
 \def\:temp{#1}\edef\:tempa{\expandafter
     \expandafter\expandafter\:gobble
     \expandafter\string\csname section\endcsname}\ifx \:temp\:tempa \else
        <.skip extra subsec toc.>%
 \fi
 -_-_-

<..skip extra subsec toc..>
 \edef\:tempa{\expandafter\expandafter\expandafter\:gobble
   \expandafter\string\csname subsection\endcsname}\ifx \:temp\:tempa \else
      {\ttl@labeltrue \ttl@addcontentsline{like#1}{#3}}%
 \fi
 -_-_-

<..titlesec for nameref..>
 \gdef\NR:Title{\a:newlabel{#3}}%
 -_-_-