It might be possible but it won't be so simple. I might post the solution later if it comes up.
The browser version is very limited as slots 2-4 are supposed to be locally stored but the plugin doesn't currently work for browsers so only slot 1 is used. I would advise to choose the download version whenever possible as even the demo saves can be accessed in the Subscribers copies without extra work. Also, the game is becoming bigger each update which makes the browser versions increasingly bulkier.