My main beef with MathJax is how it searches for equation on the entire page and renders it in place instead of using something like a custom element. E.g. in TeXZilla you can write something like:
In my own mathup library I have a similar functionality:
<math-up>x = -b+-sqrt(b^2 - 4ac) / 2a</math-up>
For MathJax to continue staying relevant it should probably do something similar (note that it is not that hard [1]).
As for the output. This is in large part due to the font being used. The default math font for me using firefox on ubuntu is indeed rather ugly. If you want something similar to the TeX output you can simply use the TeX-Gyre font face. In my documentation for mathup[2] I use Libertinus Math, which pairs very nicely with the other font faces on the page (Libertinus and Libertinus Mono). Aside: here is another example of why MathML is a superior target output then HTML+CSS as you actually have control over the font face.
And finally, as for the copy-pasting. You can download numerous browser add-ons that make copy-pasting formulas as easy as MathJax’s. I will admit this is a handy feature of MathJax, and if you want user to be able to copy-paste your expressions while not assuming they will download an add-on to do so, then MathJax is probably your number 1 choice.
2: https://runarberg.github.io/mathup/ - Note, I haven’t updated the software to target the newer MathML Core, so many expressions will not work in Chrome. You should definitely use MathJax over my library.
As for the output. This is in large part due to the font being used. The default math font for me using firefox on ubuntu is indeed rather ugly. If you want something similar to the TeX output you can simply use the TeX-Gyre font face. In my documentation for mathup[2] I use Libertinus Math, which pairs very nicely with the other font faces on the page (Libertinus and Libertinus Mono). Aside: here is another example of why MathML is a superior target output then HTML+CSS as you actually have control over the font face.
And finally, as for the copy-pasting. You can download numerous browser add-ons that make copy-pasting formulas as easy as MathJax’s. I will admit this is a handy feature of MathJax, and if you want user to be able to copy-paste your expressions while not assuming they will download an add-on to do so, then MathJax is probably your number 1 choice.
1: https://github.com/mathjax/MathJax/issues/2292#issuecomment-...
2: https://runarberg.github.io/mathup/ - Note, I haven’t updated the software to target the newer MathML Core, so many expressions will not work in Chrome. You should definitely use MathJax over my library.