This is a demo of FreeType, an open source font engine written in C++, compiled to JavaScript using Emscripten. A TrueType font (Liberation Sans Bold) is loaded in FreeType and used to render text, all entirely in JavaScript.
(Note: The demo is a proof of concept and not optimized for speed. For example, the font file is loaded and parsed every time text is rendered. Also, the code is a debug build with runtime checks for validity.)
Why was this demo done? Just to show it's possible, and definitely not to suggest people should do things this way. If you want nice fonts on the web, use WOFF.