Hello I noticed something very strange in the HTML generated by tex4ht.
I'll explain the issue and will give link to see yourself. I have one section with 843 subsection in it. All subsection use the same latex code to make a small table. The table shows OK with vertical lines showing up to subsection 118, then after that the same table starts showing with the vertical lines missing ! I thought at first I need to refresh the page or adjust the zooming but that is not it. I am not able to reproduce this on standalone MWE. It only show up using this full build of the HTML (which takes 10 hrs to complete) Here is a link to the table of content of the section <https://12000.org/my_notes/solving_ODE/current_version/inse268.htm#insu6195.htm> If you would open/click on any subsection there up to 118, you should see the small table after you scroll down a little. It should show with vertical lines OK. Now clicking on subsection 119 and any one after that the same table now shows with missing vertical lines ! Now here where the mystery becomes even more strange: I opened subsection 119 in latest Firefox, Brave, Edge and Chrome browsers (all from windows 10). Only Firefox displays the vertical lines! Same web page, same table. All other 3 browsers do not show the vertical lines in the table after subsection 118. Could any one please explain why this happens? First why the page do not display the vertical lines in the table after subsections 118 and why this problem do not show in Firefox but shows in all other browsers? Is Firefox doing the right thing and all other browsers are not? Is this tex4ht issue of generating invalid HTML somehow? But why it works for up to subsection 118? Using TL 2021 on Linux Ubuntu. ps. Here is an example of the table in question in each of the above 843 pages. There is no issue with the Latex. The table shows with vertical lines in PDF for all subsections. I think it is an HTML/Browser issue. I use mathjax mode by the way to build the HTML pages. ====================== \begin{center}% \begin{tabular}[c]{|l|l|l|}\hline case & allowed pole order for $r=\frac{s}{t}$ & allowed $O\left(\infty\right) $ order\\ \hline 1 ($L=[1]$) & $\left\{ 0,1,2,4,6,8,\cdots\right\} $ & $\left\{ \cdots,-8,-6,-4,-2,0,2,3,4,5,6,7,\cdots\right\} $ \\ \hline 2 ($L=[2]$)& $\left\{ 2,3,5,7,9,\cdots\right\} $ & no condition \\ \hline 3 ($L=[4,6,12]$)& $\left\{ 1,2\right\} $ & $\left\{ 2,3,4,5,6,7,\cdots\right\} $ \\ \hline \end{tabular} \end{center} ======================== Thank you --Nasser