Every chart in this project relies solely on semantic markup — table based — and a spread of CSS variables carried by the tags. No JavaScript required for display, and styles are progressively enhanced depending on your browser's capabilities.

Check this post written by Chris Coyier on mailto: links. "It's pretty easy to use, but as with anything web, there are lots of things to consider."

Elm is a front-end functional language that compiles to JavaScript. Read this article to understand how Elm 0.19 will makes your assets really small. Indeed Elm 0.19 comes with impressive improvements in compilation speed.