javascript - JavaScript 游戏的可疑错误

Question

所以我一直在 Codecademy 上进行一些练习，并遇到了一个小问题。目标是用java脚本创建一个石头剪刀布游戏。

当我尝试运行代码时，出现以下错误:“哎呀，再试一次。当输入是剪刀和布时，您的代码返回“纸胜”而不是“未定义””

我已将问题范围缩小到“else if”，我将在下面突出显示:

    var userChoice = prompt("Do you choose rock, paper or scissors?");
var computerChoice = Math.random();
if (computerChoice < 0.34) {
    computerChoice = "rock";
} else if(computerChoice <= 0.67) {
    computerChoice = "paper";
} else {
    computerChoice = "scissors";
} console.log("Computer: " + computerChoice);



var compare = function(choice1,choice2)
{



    if(choice1 === choice2) 
    {
        return ("The result is a tie");
    }

     else if(choice1 === "rock") 
     {

        if(choice2 === "scissors") 
        {
         return ("rock wins");
        }
     } 

        ***else if (choice2 === "paper")
        {
            return ("paper wins");***

        }

    else if (choice1 === "paper") 
    {
        if (choice2 === "rock") 
        {
            return "paper wins";
        }  

    }    
             else if (choice2 === "scissors")
            {
                return "scissors wins";
            }


                else if (choice1 === "scissors")
                {
                    if (choice2 === "rock")
                    {
                        return "rock wins";
                    }
                }

                else if (choice2 === "paper")
                {
                    return "scissors wins";
                }


};

compare(userChoice,computerChoice);

所以有趣的是，如果我编写突出显示以下内容的代码:

***

else if (choice2 === "paper") { if (choice1 === rock) {

    return ("paper wins");
        }
    }

<小时/>

然后一切正常运行。

我想知道为什么我会收到错误，如果代码看起来与我首先仅使用“else if”语句突出显示的代码完全合理？

Answer 1

您的 if 和 else if 语句未正确嵌套。

var userChoice = prompt("Do you choose rock, paper or scissors?");
var computerChoice = Math.random();
if (computerChoice < 0.34) {
    computerChoice = "rock";
} else if(computerChoice <= 0.67) {
    computerChoice = "paper";
} else {
    computerChoice = "scissors";
}
console.log("Computer: " + computerChoice);



var compare = function(choice1,choice2)
{

    if(choice1 === choice2) 
    {
        return ("The result is a tie");
    }

     else if(choice1 === "rock") 
     {

        if(choice2 === "scissors") 
        {
         return ("rock wins");
        }
        else if (choice2 === "paper")
        {
            return ("paper wins");
        }
    }
    else if (choice1 === "paper") 
    {
        if (choice2 === "rock") 
        {
            return "paper wins";
        }
        else if (choice2 === "scissors")
        {
            return "scissors wins";
        }
    }
    else if (choice1 === "scissors")
    {
        if (choice2 === "rock")
        {
            return "rock wins";
        }
        else if (choice2 === "paper")
        {
            return "scissors wins";
        }
    }
};

compare(userChoice,computerChoice);