An earlier answer ("converting to HTML") addresses the issue of converting existing (La)TeX documents for viewing on the Web as HTML.
Better font availability and the support for new Web standards means that there are now several possibilities for good rendering of mathematics on the web.
The available OpenType math fonts are discussed in OpenType fonts
safariand other browsers using te same underlying html rendering libraries. At the current time it is not supported by Chrome or Edge browsers. MathML in the page may be rendered by MathJax, with an output identical to its TeX r.endering. MathJax uses a variant of MathML as its intermediate format)
The MathJax project's site also
allows you to download your own copy and install it on one of your
MathJax is open source software.