Question

我正在编写一个可以制造无钥匙汽车的代码。因此，当您键入年龄时，应该输入以下内容：

1）如果他们说自己未满18岁，请回答： “抱歉，您还太年轻，无法驾驶这辆车。请关机”

2）如果他们说自己18岁，请回答： “恭喜您驾驶的第一年。祝您旅途愉快！”

3）如果他们说年满18岁，请回答： “加电。享受旅程！”

我应该使用JS条件，例如：如果，其他，否则

当我说“ else”（第三个条件）时，如果condition1为false而condition2为false，则应执行代码块。因此，它们都是错误的。我尝试使用'else if'代替'else'，但是它起作用了，但是我不明白它们之间的区别。

var age = prompt("Good day! What is your age?:");
if (age < 18) {
    alert("Sorry, you are too young to drive this car. Powering off");
} else if (age === 18) {
    alert("Congratulations on your first year of driving. Enjoy the ride!");
} else (age > 18) {
    alert("Powering On. Enjoy the ride!");
}

我期待的是带有正确文本的警报消息，但是它给我一个错误的最后一个'else'：未捕获到的SyntaxError：意外令牌{

Answer 1

否则不应该有条件，因为else的代码在没有条件匹配时就执行。

编辑：如Maheer Ali所述，您还应该将var age转换为int。

var age = prompt("Good day! What is your age?:");
    age = parseInt(age);

if (age < 18) {
    alert("Sorry, you are too young to drive this car. Powering off");
} else if (age === 18) {
    alert("Congratulations on your first year of driving. Enjoy the ride!");
} else {
    alert("Powering On. Enjoy the ride!");
}

Answer 2

else不应具有以下条件：（删除(age > 18)部分）

还要确保将字符串值转换为int进行比较（<> =）

var age = prompt("Good day! What is your age?:");
if (age < 18) {
    alert("Sorry, you are too young to drive this car. Powering off");
} else if (age === 18) {
    alert("Congratulations on your first year of driving. Enjoy the ride!");
} else {
    alert("Powering On. Enjoy the ride!");
}

Answer 3

删除您的其他

中的疾病

var age = prompt("Good day! What is your age?:");

// Betwen 0 and 17 years old
if (age < 18) {
    alert("Sorry, you are too young to drive this car. Powering off");
}
// Exactly 18 years old
else if (age === 18) {
    alert("Congratulations on your first year of driving. Enjoy the ride!");
}
// We don't care about her age here :-D
else {
    alert("Powering On. Enjoy the ride!");
}

为什么我收到与意外令牌相关的错误，而不是“ else”和“ else if”

3 个答案: