语法错误：JavaScript中的意外标识符

Question

运行以下代码时出现语法错误：

var userAnswer = 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.'") }

代码比上面的代码多，但我知道错误源自那里。

Answer 1

您的if语法错误。它应该是这样的：

if (userAnswer === "yes")

Answer 2

你的if-then语法似乎错了，它应该是if (expression) {} else {}。您还在if表达式（userAnswer = ("yes")）中使用赋值运算符，而不是测试相等性（userAnswer == "yes"）

尝试以下方法：

if (userAnswer == "yes") {
    console.log("You and Bieber...")
}
else {
    console.log("Oh no! ...")
}