So, yeah... A few other tweaks and fixes, but offline mode is the big addition here.
You don't have to have known that you were going offline, YMS copes. Let's say you're working on an online script, the first time you go offline, you're asked if you'd like to continue offline, or just always continue automatically.
Your worked gets saved locally by your browser, and when you reconnect, the tab will catch-up. May take a moment, depending on how long you've been offline, but generally, it's all pretty invisible... you're online, you're offline, you're online, you're up to date.
If you've closed the browser or the tabs you're working on, your work is safe. When you reconnect to the online script, you're asked if you want to re-synch (with the option to always re-synch). Your work is merged with whatever your collaborators, if any, have been up to, and if you have backups set up, a backup of your offline work is taken.
As ever, let me know about any problems, issues, or suggestions.