Question

以下代码来自我的课程，但无法正常工作。

我试图尽我所能想到的一切

var eatSteak = confirm("Do you eat steak?");
var confirmSteak = confirm("You like Steak!");
var confirmNoSteak = confirm("Here's a tofu stir-fry");
var howOld = prompt("How old are you?");
var howNotOld = confirm("No Sake for you!");
var sakeForYou = confirm("Sake for you!");
var tryAgain = confirm("TRY AGAIN!");
if (eatSteak == true) {
  alert(confirmSteak);
} else {
  alert(confirmNoSteak);
}
if (howOld < 21) {
  alert(howNotOld);
} else if (howOld >= 21) {
  alert(sakeForYou);
} else {
  alert(tryAgain);
}

控制台未显示任何错误消息

Answer 1

confirm()仅应用于提问。如果只想为消息设置变量，则不应调用confirm()。像这样的语句

var confirmSteak = confirm("You like Steak!");

应该是

var confirmSteak = "You like Steak!";

此外，当您测试howOld时，请检查它们是否小于21，然后检查它们是否至少为21。这是仅有的两种可能性，它永远都不可能到达最后else块。因此，您可以只使用if和else －不论它们是否清酒。

var eatSteak = confirm("Do you eat steak?");
var confirmSteak = "You like Steak!";
var confirmNoSteak = "Here's a tofu stir-fry";
var howOld = prompt("How old are you?");
var howNotOld = "No Sake for you!";
var sakeForYou = "Sake for you!";
if (eatSteak == true) {
  alert(confirmSteak);
} else {
  alert(confirmNoSteak);
}
if (howOld < 21) {
  alert(howNotOld);
} else  {
  alert(sakeForYou);
}

Answer 2

一个简单的规则。仅在要获得用户输入时才使用prompt和confirm。

if (confirm("Do you eat steak?") == true) 
   alert('You like Steak!')
else 
   alert('Heres a tofu stir-fry');



//Here is a variable which stores the user input
var age = prompt("How old are you?");

if (age < 21)
  alert('No Sake for you!')  
else 
  if (age > 21) 
    alert('Sake for you!')  
  else 
    alert('TRY AGAIN!');

Javascript if / else语句有帮助，这段代码我在做什么错？

2 个答案: