Using web2js, the Pascal source of tex is compiled to WebAssembly; the latex format is loaded (without all the hyphenation data), and

\documentclass[margin=0pt]{standalone}
\def\pgfsysdriver{pgfsys-ximera.def}
\usepackage{tikz}

is executed. Then core is dumped; the resulting core is compressed, and by reloading the dumped core in the browser, it is possible to very quickly get to a point where TikZ can be executed. By using an SVG driver for PGF along with dvi2html, the DVI output is converted to an SVG.