IJ can correct me if I'm wrong, but John Earnest (AKA Internet Janitor) is the creator of Octo, which is hosted from his Github. However, the program you wrote should be automatically saved in your browser. That being said, you should probably make a note to occasionally download backups of your work (Toolbox > Binary Tools > Save .8o).
What do you mean by "it won't open?" Is Octo not loading on your browser? Or are you unable to run your game at all? Are you downloading 8o files and trying to run them?