我在这里做错了什么？否则如果

Question

所以我在这里遇到了麻烦。这是一个作业，基本上我问的问题是 3+3 是什么，用户可以将正确答案输入... 6，它会说 "Correct!" 如果它不是数字，那么它会说 "please type in a number..." 如果它是 5 或 7 那么它会说 "Very close, try again" 如果它不是 5 6 或 7 它会说 "incorrect" 如果没有输入它应该说 "come on, you can do it." 我是什么在这里做错了？？？？目前它所做的只是说是，6 是正确的！即使我输入不同的数字

var question;
question = window.prompt("What's the sum of 3+3?", "");

question = parseFloat(question);
if (isNaN(question)) {
  output = "Please enter a number";
} else if (question = 6) {
  output = "Yes " + question + " is correct!";
} else if (question = 5) {
  output = "Very close, try again!";
} else if (question = 7) {
  output = "Very close, try again!";
} else if (question = null) {
  output = "Come on, you can do it!!";
} else {
  output="Incorrect, Please try again"
}

document.write(output);

Answer 1

在您的代码中，您在 if 中使用了 question=8，这意味着您将 8 分配给了 question。

= means assign and == mean comparing

试试这个：

var question; 
question = window.prompt("What's the sum of 3+3?","");

question = parseFloat(question);
if (isNaN(question))
{
    output= "Please enter a number";    
}else if (question==6)
{
    output="Yes " +question+" is correct!"; 
}else if (question==5){
    output="Very close, try again!";    

}else if (question==7){
    output="Very close, try again!";
}else if (question==null){
    output="Come on, you can do it!!";
}

else {output="Incorrect, Please try again"}





document.write(output);

Answer 2

如@Anik Islam Abhi 的回答和评论所述 = 与 == 不同。

==是比较运算符(read more)

= 是赋值运算符 (read more)

现在，您需要做的是决定用户输入nothing的方式是什么？我假设你指的是任意数量的空格。

你可以做的是始终从输入的答案中删除所有空格，如果用户仍然输入 nothing 那么你知道你应该打印 "Come on, you can do it!!"

// get the question and remove all whitespace so we know if the user enter an empty string
var question = window.prompt("What's the sum of 3+3?","").trim().replace(' ','');
    
if (!question) {                              // nothing
    output = "Come on, you can do it!!";
} else if(isNaN(question)) {                  // not a number
output = "Please enter a number";  
} else if (question == 6) {                   // correct answer
    output = "Yes " +question+" is correct!"; 
} else if (question == 5 || question == 7) {  // close answer
    output = "Very close, try again!";    
} else {
    output="Incorrect, Please try again"      // incorrect answer 
}

document.write(output);

我在这里做错了什么？否则如果

What am I doing wrong here? Else if

javascript

if-statement