If/Else 语句仅在满足 else 条件的情况下运行

Question

我正在尝试制作一个程序，讨论您最喜欢的科目以及您是右脑还是左脑。

function questionGame() {
var user = prompt("Are you RIGHT brained, LEFT brained, a bit of BOTH, or NEITHER?").toUpperCase();

switch (user){
 case 'RIGHT':
    var user1 = prompt("You like Art?").toUpperCase();
    if (user1 = 'YES' || 'YEAH') {
        alert("Sweet. You should check out LadyBeeSweets, she is the next michelangelo.");
    } else if (user1 = 'NO') {
        alert("Alright, ok, um, then do you like anything?");   
    } else {
        alert("I'm sorry, I don't understand " + user1 + ", please respond YES or NO next time, thank you!");
    };
     break;
 case 'LEFT':
     var user2 = prompt("Oh nice! Me too, I love my tech! Do you have a Linux-Based Operating System?").toUpperCase();
     if (user2 = 'YES') {
        alert("Sweet, me too!");   
     } else if (user2 = 'NO') {
        alert("Oh, you should definitely give one a try!")   
     } else {
       alert("I'm sorry, I don't understand " + user2 +", next time please respond with YES or NO.");  
     };
     break;
 case 'BOTH':
     var user3 = prompt("Interesting, so do you like Whales?").toUpperCase();
     if (user3 = 'YES' || 'YEAH') {
        alert("Cool."); 
     } else if (user3 = 'NO' || 'NOPE') {
        alert("You, MONSTER!"); 
     } else {
        alert("Hmm, whats that? I don't know if you like whales or not. Please reply YES or NO next time!"); 
     };
     break;
 case 'NEITHER':
     var user4 = prompt("Hmm, ok. I'm a left brainer! Do you care that I'm a Left Brainer? YES or NO?").toUpperCase();
     if (user4 = 'YES' || 'YEAH') {
        alert("Thanks for caring!");  
     } else if (user4 = 'NO' || 'NOPE') {
       alert("Wow, thanks a lot, bro.");   
     } else {
         alert("I couldn't understand " + user4 + ", please reply YES or NO next time, thank you");
     };
     break;
 default:
     alert("I'm sorry, I don't understand " + user + ", try again and chose either 'RIGHT', 'LEFT', 'BOTH', or 'NEITHER'.");
     questionGame();
     
    };
};

但是，当您在第一个提示中输入 'Left' 时，它会询问您是否使用基于 linux 的操作系统，即使您键入 'no' 或类似 'guhgriubcrhmiecrc'，它仍然运行第一个 if 语句的代码块。我感谢所有答案。对了，这是JavaScript.

Answer 1

您在 if (user2 = 'YES')

等语句中使用赋值运算符 = 而不是比较运算符 == 或 ===

Answer 2

正如 Jorg 提到的，您正在分配一个变量，而不是比较它。既然您已经确定这是您所做的事情，请通过将文字放在比较的左侧来避免将来这样做。

if ('YES' === user2) {
        alert("Sweet, me too!");   
}
// If you forget to use multiple equals again, this code will throw an error and the problem will be more obvious
if ('YES' = user2) {
        alert("Oops!");   
}

If/Else 语句仅在满足 else 条件的情况下运行

If/Else statement only runs if code even if else condition is satisfied

javascript

if-statement

prompt

switch-statement