TeX is the gold standard for typesetting of mathematical content. MathLive provides a JavaScript implementation that faithfully reproduces the output of TeX. MathLive supports over 800 TeX commands. (from the product's site)

A good alternative for Mathquill with virtual keyboard. I use this lib coupled with KaTeX.js for my project https://mathrelay.com and it works quite well. A good choice if you want something like Grapher input (macOS) on your website. Thanks to @arnog for developing and maintaining the lib

Oh, this looks cool, will surely try. :)