I've started playing with TiKZJax, a system for converting TikZ images to SVG, and embedding them in HTML pages. I do like this tool a lot, but I'm having some troubles with mathematical formulas (LaTeX) in TikZJax nodes. The problem is that some basic mathematical symbols do not render correctly.
Here you can see a webpage with two MWEs.
The first one is derived from an image I was preparing, where I first noticed the issue. The negative y axis labels have a "times" sign instead of the expected minus. The two texts roughly at (3,3) and (6,6) are two "experiments". One should be $-2$ and the other has a bunch of random symbols $\hbar \pi \times \otimes \sum$. The third and the fourth won't render correctly.
The second MWE is the same you can find in the TikZJax demo here, but with $-\y$ in place of $\y$. Again, the minus sign won't render correctly.
The compilation log I see from the console does not complain about anything.
I tried inspecting the "times" symbol that appears in place of the minus sign. I am no expert at all, but from what I understand, this should correspond to the £ symbol in the font family cmsy10:
<text alignment-baseline="baseline" y="61.57359313964842" x="-51.62625122070311" style="font-family: cmsy10; font-size: 12;">£</text>.
I looked for a table of cmsy10 fonts and I found one in this TeX StackExchange thread. It seems to me that the minus sign is two cells to the right from the times sign. I am not sure how to read the "coordinates" in the table. Anyway from this site £ corresponds to 163, and 161 corresponds to an inverted exclamation mark "¡".
I created an HTML file with the SVG code for (a version of) the first MWE, and changed the pound symbols into inverted exclamation marks. This produces the expected minus signs.
Could it be that the author of TikZJaX got the mapping of some math symbols wrong? Or am I getting it all wrong? In the latter case, can something be done to get the correct minus signs (and other symbols)?
PS By the way, I noticed that the TikZJaX demo here does not actually map the fonts to the correct font family. I think this is because something goes wrong with the link to the CSS file in the header of the webpage. I'm guessing this because I get a similar rendering if I comment out the link to the CSS file, which contains a list of font families.