By Igor A. Kotelnikov. Not available in the public domain?
<..TextBook.4ht..>
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% TextBook.4ht 2014-07-12-22:36 %
% Copyright (C) 2002--2009 Eitan M. Gurari %
<.TeX4ht copyright.>
\def\thesection {\@arabic\c@section}
\def\@seccntformat#1{\S\csname the#1\endcsname\quad}
\input book.4ht
\ConfigureToc{section}
{\HCode{<span class="sectionToc">}\S}
{~}
{}
{\HCode{</span><br\xml:empty>}}
\ConfigureToc{subsection}
{\HCode{<span class="subsectionToc">}~~\S}
{~}
{}
{\HCode{</span><br\xml:empty>}}
\ConfigureToc{subsubsection}
{\HCode{<span
class="subsubsectionToc">}~~~~\S}
{~}
{}
{\HCode{</span><br\xml:empty>}}
\Hinput{TextBook}
\endinput
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