Boxed

<..configure html-mltx amsmath ..>+

\Configure{boxed}
    {\ifmathltx \HCode{\string\boxed\l:brace}%
     \else     \HCode{<span class="boxed">}\IgnorePar\fi}
    {\ifmathltx \HCode{\r:brace}%
     \else \HCode{</span>}\fi}
\Css{.boxed{border: 1px solid black; padding-left:2px;
                                      padding-right:2px;}}

-_-_-

4.1 Boxed