userAnswer = prompt("Do you want to race Bieber on stage?");
var userAnswer = "Yes";
if(userAnswer === "Yes")
console.log("You and Bieber start racing. It's neck and neck! You win by a shoelace!");
else // "otherwise"
console.log("Oh no! Bieber shakes his head and sings 'I set a pace, so I can race without pacing.'");
Replace this line with your code.