EpicEditor is an embeddable JavaScript Markdown editor with split fullscreen editing, live previewing, automatic draft saving, offline support, and more. For developers, it offers a robust API, can be easily themed, and allows you to swap out the bundled Markdown parser with anything you throw at it.
Are there any plans to implement mathjax (http://www.mathjax.org/) just like http://math.stackexchange.com/.
It would be a great feature.