带有争论的函数并在 javascript 中创建变量

Question

我对编码完全陌生，我正在尝试创建一个函数来请求用户输入，将输入存储在要动态创建的变量中，最后输出变量的转换；我的代码就在下面。谢谢：function dogHuman(yes, no) {  var humanAge = ((dogAge - 2) * 4) + 21;  var haveDog = prompt("Do you have a dog? " + "yes" + " or " + "no");  if (haveDog == yes) {    var dogAge = prompt("How old is your dog? ");    alert("If your dog were human, it would be " + humanAge + " years old");  } else if (haveDog == no) {    alert("Thank you for you attention");  } else {    var haveDog = prompt("Do you have a dog? " + "yes" + " or " + "no" + yes + no);  }}dogHuman();

Answer 1

主要问题是haveDog == yes& haveDog == no。这里yes&no是字符串。所以不得不比较喜欢'haveDog === 'yes'。没用===。其次humanAge，仅当用户键入时才计算，yes否则它将undefined

function dogHuman(yes, no) {

  var haveDog = prompt("Do you have a dog? " + "yes" + " or " + "no");

  if (haveDog === 'yes') {

    var dogAge = prompt("How old is your dog? ");

    var humanAge = ((dogAge - 2) * 4) + 21;

    alert("If your dog were human, it would be " + humanAge + " years old");

  } else {

    alert("Thank you for you attention");

  }

}

dogHuman();

Answer 2

我不确定问题是什么，所以我将回顾一下我注意到的所有内容：

1. dogHuman在没有任何参数的情况下调用，并且查看您的代码，它可能不应该有任何参数。

2. Javascript（事实上，大多数语言）按顺序做事，所以var humanAge = ((dogAge - 2) * 4) + 21;应该dogAge首先确定。

3. 既然haveDog是拿一个prompt，你可能想比较haveDog而"yes"不是仅仅yes。

4. "Do you have a dog? " + "yes" + " or " + "no"可以重写为"Do you have a dog? yes or no"

变量设置一次；每次运行它们时，它们都不会重新运行您设置的值；这种误解很常见，这也是我认为早期humanAge定义的来源。

Answer 3

你有几个问题，

1. 将适当的参数传递给函数调用。

2. 在提示之后移动humanAge分配dogAge，因为这需要首先发生。

3. 确保不要引用你的变量

function dogHuman(yes, no) {

  var haveDog = prompt("Do you have a dog? " + yes + " or " + no);

  if (haveDog === yes) {

    var dogAge = prompt("How old is your dog? ");

    var humanAge = ((dogAge - 2) * 4) + 21;

    alert("If your dog were human, it would be " + humanAge + " years old");

    dogHuman(yes, no); // Recursion

  } else {

    alert("Thank you for you attention");

  }

}

dogHuman('yes', 'no'); // Pass your parameters into the call