Question

我正在制作一个石头剪刀游戏，我想要警报来确定谁选择了什么以及谁赢了，但警报不会弹出。我发现有多个错误回过头来修复它们，仔细检查了一切，甚至进行了三重检查，但警报仍然没有弹出？

这是三个功能中的一个（它们都相似）：

function rock() {
  var computerChoice = Math.random();
  if (computerChoice < 0.34) {
    computerChoice = "rock";
  } else if (computerChoice < 0.67) {
    computerChoice = "paper";
  } else {
    computerChoice = "scissors";
  }
}
if (computerChoice === "rock") {
   alert("Link and Computer both chose Rock! It's a Tie!");
} else if (computerChoice === "scissors") {
   alert("Link chose Rock and Computer chose Scissors! Computer took a heart of damage!");
} else {
   alert("Link chose Rock and Computer chose Paper! Link took a heart of damage!");
}
}

Answer 1

您无法返回提醒。警报是一种方法调用。删除警报前面的返回，警报将打开：

if(computerChoice === "rock"){
    alert("Link and Computer both chose Rock! It's a Tie!");
}

Answer 2

您不需要退货。所以，改变这个：

if(computerChoice === "rock"){
  return alert("Link and Computer both chose Rock! It's a Tie!");
}

到此：

if(computerChoice === "rock"){
  alert("Link and Computer both chose Rock! It's a Tie!");
}

Answer 3

我认为问题出在所示的界线上：

function rock() {
  var computerChoice = Math.random();
  if (computerChoice < 0.34) {
    computerChoice = "rock";
  } else if (computerChoice < 0.67) {
    computerChoice = "paper";
  } else {
    computerChoice = "scissors";
  }
} // <-- I don't think you want this closing brace here
if (computerChoice === "rock") {
   alert("Link and Computer both chose Rock! It's a Tie!");
} else if (computerChoice === "scissors") {
   alert("Link chose Rock and Computer chose Scissors! Computer took a heart of damage!");
} else {
   alert("Link chose Rock and Computer chose Paper! Link took a heart of damage!");
}
}

我指出的结束括号结束了rock()功能。就目前而言，rock()功能实际上并没有做任何事情;它随机地为一个局部变量赋值"rock"，"paper"或"scissors"，但该函数在没有使用变量的情况下结束，因此该值将丢失。

当JavaScript首次加载到浏览器中时，其余代码将运行一次。此时，computerChoice将为undefined，因此您将收到JavaScript错误。

如果我们删除错误的大括号并重新格式化代码，我们会得到以下结果：

function rock() {
  var computerChoice = Math.random();
  if (computerChoice < 0.34) {
    computerChoice = "rock";
  } else if (computerChoice < 0.67) {
    computerChoice = "paper";
  } else {
    computerChoice = "scissors";
  }

  if (computerChoice === "rock") {
     alert("Link and Computer both chose Rock! It's a Tie!");
  } else if (computerChoice === "scissors") {
     alert("Link chose Rock and Computer chose Scissors! Computer took a heart of damage!");
  } else {
     alert("Link chose Rock and Computer chose Paper! Link took a heart of damage!");
  }
}

我多次运行此功能。每次它随机警告三条消息中的一条。

Answer 4

这种方法很有用，并且使用较少的弯路来实现目标：）

function rock() {
  var replies = new Array(
    'Link and Computer both chose Rock! It\'s a Tie!',
    'Link chose Rock and Computer chose Scissors! Computer took a heart of damage!',
    'Link chose Rock and Computer chose Paper! Link took a heart of damage!');
  alert(replies[Math.floor(replies.length * Math.random())]);
}

澄清： Math.random（）返回[0..1＆gt;
范围内的浮点数 replies.length * Math.random（）返回范围为[0..3＆gt;
的浮点数 Math.floor（replies.length * Math.random（））返回0,1或2.

不从if语句打开的警报

4 个答案: