JavaScript if "x = (a || b || c)" 语句不起作用

我正在用 javascript 编写一个简单的三角程序，我的 if 和 while 语句无法正常工作，因为它们只有在第一个条件为真时才会通过，即如果您输入正弦，它将起作用，但如果您输入余弦或正切，则不会。

<script language="JavaScript">
var opposite = 1
var adjacent = 1
var hypotenuse = 1
var sct = "SohCahToa"
while (!(sct == ("Sine" || "Cosine" || "Tangent"))) {
    sct = prompt("Sine (unknown adjacent) / Cosine (unkown opposite side) / Tangent (unknown hypotenuse)")
    if (!(sct == ("Sine" || "Cosine" || "Tangent"))) {
        alert("Spelling error, please try again")
    }
}
if (sct == ("Sine" || "Cosine"))
    hypotenuse = prompt("What is the hypotenuse")
if (sct == ("Sine" || "Tangent"))
    opposite = prompt("What is the opposite side")
if (sct == ("Tangent" || "Cosine"))
    adjacent = prompt("What is the adjacent side")

谢谢 （将代码另存为.html以进行测试）

所有多重比较如下所示：

if (sct == ("Sine" || "Cosine" || "Tangent"))

需要改成这样：

if (sct == "Sine" || sct == "Cosine" || sct == "Tangent")

解释一下，当你这样做时("Sine" || "Cosine" || "Tangent")，其计算结果为"Sine" so if (sct == ("Sine" || "Cosine" || "Tangent"))是相同的if (sct == "Sine")这显然不是你想要的。

这是应用了所有更正的代码：

var opposite = 1
var adjacent = 1
var hypotenuse = 1
var sct = "SohCahToa"
while (!(sct == "Sine" || sct == "Cosine" || sct == "Tangent")) {
    sct = prompt("Sine (unknown adjacent) / Cosine (unkown opposite side) / Tangent (unknown hypotenuse)")
    (!(sct == "Sine" || sct == "Cosine" || sct == "Tangent")) {
        alert("Spelling error, please try again")
    }
}
if (sct == "Sine" || sct == "Cosine")
    hypotenuse = prompt("What is the hypotenuse")
if (sct == "Sine" || sct == "Tangent")
    opposite = prompt("What is the opposite side")
if (sct == "Tangent" || sct == "Cosine")
    adjacent = prompt("What is the adjacent side")