请问哪里错了?运行结果怎么总是否定语句

请问哪里错了?运行结果怎么总是否定语句
console.log("Suddenly,Bieber stops and says,'Who wants to race me?'")
var userAnswer = prompt
prompt("Do you want to race Bieber on stage?")
if (userAnswer === "yes")
{
console.log("You and Bieber start racing.It's neck and neck!You win by a shoelace!")
}
else
{
console.log("Oh no!Bieber shakes his head and sings 'I set a pace,so I can race without pacing.'")
}