document.addEventListener('keydown', function(event) {
console.log("event.key:_", event.key, "_event.code", event.code)
if(+event.key) console.log("num") //addCharacter(event.key)
else if(event.key == "-") console.log("minus") //minus();
else if(event.key == "+") console.log("plus")
else if(event.key == "=")console.log("result")
else if(event.key == "/")console.log("delim")
else if(event.key == "*")console.log("multiply")
else console.log("nepon1")
});