在事实之后为变量赋值

Question

我正在学习和搞乱内置的Chrome控制台。请原谅我的结构。有没有更好的领域我可以问这些初学者的问题？

我无法使用两种变体：

如果我对学习JavaScript不感兴趣，并输入一个“否”响应，我想要一个新的提示来显示分配一个newInterest变量，然后继续警告'那很好'。

var interestLevel = prompt('Hello, are you interested in learning JavaScript?')
if (interestLevel == "yes") {
  alert('Wonderful, welcome!')
}
if (interestLevel == "no") {
  var newInterest = prompt('Then what are you interested in?')
}

第二个应该在“是”响应之后结束，但它实际上继续询问第二个提示，但不应该是这种情况。

var interestLevel = prompt('Hello, are you interested in learning JavaScript?')
if (interestLevel == "yes") {
  alert('Wonderful, welcome!')
}
if (interestlevel == "no") {
  alert('That sucks')
}
/* press ok to make the box go away so that the next prompt below will show up */
var newInterest = prompt('Then what are you interested in?')

编辑：我根据每个人的建议修改了一切。我的下一个目标是弄清楚如何使下面的功能。

var interestLevel = prompt('Hello, are you interested in learning JavaScript?')
if (interestLevel == "yes") {
  alert('Wonderful, welcome!')
}
else if (interestLevel == "no") {
  alert('That sucks')
  /* press ok to make the box go away so that the next prompt below will show up */
  var newInterest = prompt('Then what are you interested in? html? css?')
if (newInterest === "html"){alert('let\'s get started with html!')}
else if (newInterest === "css"){alert('I don\'t know css')
}
    else {alert('please input css or html')}
}

Answer 1

你有两个问题：

1. 要仅在第一个答案为“否”时显示第二个提示（newInterest），请将其移至if (interestlevel == "no")代码块中。
2. 您的变量大小写并不总是匹配。上述interestlevel声明中的if应更改为interestLevel。

看这个例子：

var interestLevel = prompt('Hello, are you interested in learning JavaScript?')
if (interestLevel == "yes") {
  alert('Wonderful, welcome!')
}
if (interestLevel == "no") {
  alert('That sucks')
  /* press ok to make the box go away so that the next prompt below will show up */
  var newInterest = prompt('Then what are you interested in?')
}

这并不重要，但是对于更大的脚本，你可以用if语句替换你的第二个else if语句，只有在第一个if语句返回false时才会运行。这样，如果第一个条件是true，则根本不会检查第二个if语句（因为它的结果无关紧要）并且可能会节省几纳秒。

更新：

如果要将此代码转换为函数，请将其包装在函数语句中，如下所示：

function myFunction() {
  var interestLevel = prompt('Hello, are you interested in learning JavaScript?')
  if (interestLevel == "yes") {
    alert('Wonderful, welcome!')
  }
  if (interestLevel == "no") {
    alert('That sucks')
      /* press ok to make the box go away so that the next prompt below will show up */
    var newInterest = prompt('Then what are you interested in?')
  }
}

然后调用它，像这样：

myFunction();

Answer 2

仅在此人未回答时提示。

var interestLevel = prompt('Hello, are you interested in learning JavaScript?')
if (interestLevel == "yes") {
  alert('Wonderful, welcome!')
}
if (interestlevel == "no") {
  alert('That sucks')
}
/* press ok to make the box go away so that the next prompt below will show up*/
if(interestLevel == "no")
    var newInterest = prompt('Then what are you interested in?')

或者这也可以，取决于您喜欢如何组织代码。

var interestLevel = prompt('Hello, are you interested in learning JavaScript?')
if (interestLevel == "yes") {
  alert('Wonderful, welcome!')
}
if (interestlevel == "no") {
  alert('That sucks');
  var newInterest = prompt('Then what are you interested in?')
}
/*press ok to make the box go away so that the next prompt below will show up */