A markdown editor, when you eidt a document, you can swith between edit and preview by context menu, the content you wrote will be saved automatically, you don't need to worry the lose of your work.
The instruction only work on linux
open terminal, enter the markown-editor directory
cd markdown-editorthen start python http server by the following command
python -m SimpleHTTPServerinstall browser plugin markdown here for your chrome or firefox.
say you installed markdown here for firefox, enter the 127.0.0.1:8000 to your the address bar of your firefox, you will get the editor. Now you can write your document by markdown in that browser window, and preview or switch back to editor by the right click and choose Markdown Toggle from the context menu.
hope you enjoy it.