var slaying = true;
var youHit = Math.floor(Math.random() * 2);
var damageThisRound = Math.floor(Math.random() * 5 + 1);
var totalDamage = 0;

while(slaying) {
    if(youHit) {
        console.log("Nice! You hit the dragon!");
        totalDamage += damageThisRound;

        if(totalDamage >= 4) {
            console.log("Kablamo! You have slain the dragon!");
            slaying = false;
        } else {
            youHit = Math.floor(Math.random() * 2);
        }
    } else {
        console.log("Smooth move Ferguson. You missed and have been burnt to a crisp by the dragon");
        slaying = false;
    }
}