web-cheat/katex.html
<!doctype html>
<html lang=en>
<head>
<meta charset=utf-8>
<title>Client-side KaTeX</title>
<script src="https://cdnjs.cloudflare.com/ajax/libs/KaTeX/0.13.11/katex.min.js" integrity="sha512-1kNZVA50gKlorLAWU83+SdOAUwABzfFFQ4WuOAZTeS/UhNhnm9zU7rDv/Q5NEzSnr5u2L6uhR/+8icjjmHjSnQ==" crossorigin="anonymous" referrerpolicy="no-referrer"></script>
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/KaTeX/0.13.11/katex.min.css" integrity="sha512-J8je2SgrCzA7hNBeiCJiA6oETHTTdp3We3EriOgJp6POycGLcDXj5dSwWlAPQcYGeaQ4N3uf30aOg/Nt5pxW2g==" crossorigin="anonymous" referrerpolicy="no-referrer" />
</head>
<body>
</body>
<script>
document.getElementsByTagName('body')[0].innerHTML = katex.renderToString('\\frac{1}{\\sqrt{2}}')
</script>
</html>