Are you using the latest (1v92) Espruino firmware? Earlier firmwares didn't support bonding, which Windows needed to work. With it, you shouldn't need the Web IDE open and connected once the device has been programmed.
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
Are you using the latest (1v92) Espruino firmware? Earlier firmwares didn't support bonding, which Windows needed to work. With it, you shouldn't need the Web IDE open and connected once the device has been programmed.
And try
kb.KEY[" "]
for the space key...