Noteflight

Noteflight is an easy to use, full-featured application to write, play back and share musical scores. Write sheet music using our award winning notation editor and become part of the world's best online music composition community. Share your scores to get feedback from other composers and musicians and learn from viewing and listening to their shared scores. Noteflight works with all modern web browsers and on many mobile devices, including iPhone, iPad and Android phones and tablets.

Screenshots from Chrome Web Store