Is there JavaScript which will do this?
I would generate a 256 bit password using 99 dice throws, enter it into JavaScript on an offline computer (like using bitaddress.org) and get an address to send Bitcoin to, so that I can store them cold.
What I don’t want, as would be done in bitaddress.org, is for my private key to be shown on the screen in case there is screenshot malware on the computer. (N.B. I can defeat key-logging by scrambling the entry of the dice throws using a mouse).
When I wish to transfer the Bitcoin to, say, a Blockchain account, I can go to an offline computer, generate the private key from the password using bitaddress.org and then on another computer which is online carry out the transfer.
The procedure seems pretty safe to me.