\subparagraph{} Equivalent In Html

I have my habits with LaTeX, then in HTML I don’t know which element can replace the LaTeX’s \subparagraph{} command.
isn’t a good idea because it is the equival

Solution 1:

You could use a div element as the paragraph subsitute and p elements as subparagraphs, with additional class for styling, this could represent your LaTeX document structure.

\paragraph{Introfoo}
Introduction lorem lorem

  \subparagraph*{}
  Foobar lorem impsum ugh

  \subparagraph*{}
  Foobar lorem impsum ugh

would translate to: The h3 tag is just a suggestion, the level depends on your other structure around this.

<div class="paragraph">
  <h3 class="paragraph">Introfoo</h3>
  <p class="paragraph">    
    Introduction lorem lorem
  </p>
  <p class="subparagraph">
    Foobar lorem impsum ugh 1
  </p>

  <p class="subparagraph">
    Foobar lorem impsum ugh 2
  </p>
</div>

Solution 2:

LaTeX' \paragraph is a heading element, the next-to-smallest one, so I'd map it to <h5>, leaving <h6> for subparagraphs, and use CSS to give them display:inline-block (run-in headers) and appropriate other styling as desired. This will leavel h1-h4 for title-and-or-chapter, section, subsection, subsubsection.