JavaScript 多转换器

Question

我在 javascript 中有这 3 个函数(多转换器)，但我不明白为什么我不能让程序显示结果。

function WhichConversion () {
    var answer = window.prompt( " Welcome to the Mutliconverter! What do you want to convert?  ( Dollars, Francs, Knots");
    if (answer == "Dollars", "Knots", "Francs"){
        return true;
    } else {
        return false;
    }
}
function AskForValue () {
    var answer = window.prompt( " Enter a Value to Convert")
    return answer;
}
while (WhichConversion()) {
    var ConversionType = WhichConversion();
    var ConversionValue = AskForValue();
    var resultMessage = " The result is ";
    var result = 0;

    if (ConversionType == "Dollars"){
        resultMessage += DollarstoEuros(Number(ConversionValue))
        .toString();
    }else if (ConversionType == "Francs"){
        resultMessage += SwissFrancsToEuros(Number(ConversionValue))
        .toString();
    }else if (ConversionType == "Knots"){
        resultMessage += KnotstoKph(Number(ConversionValue))
        .toString();
    }else{
        resultMessage = " Pay attention! That conversion is not supported.";
    }
}
console.log(resultMessage);

Answer 1

用于检查要使用哪种转换的 if 语句只有一项检查 answer == "Dollars"。要使脚本适用于其他值，您需要创建多个检查:

if (答案 == "美元"|| 答案 == "纽特"|| 答案 == "法郎"){

有关工作示例，请检查以下代码:

var currentCurrency = '';

function WhichConversion () {
    var answer = window.prompt( " Welcome to the Mutliconverter! What do you want to convert?  ( Dollars, Francs, Knots");

    currentCurrency = answer;

    return answer !== null
}
function DollarstoEuros(value){
return value * 12;
}

function AskForValue () {
    var answer = window.prompt( " Enter a Value to Convert")
    return answer;
}

while (WhichConversion()) {
    var ConversionValue = AskForValue();
    var result = 0;
    var resultMessage = " The result is ";


    if (currentCurrency == "Dollars"){
        resultMessage += DollarstoEuros(Number(ConversionValue))
        .toString();
    }else if (currentCurrency == "Francs"){
        resultMessage += SwissFrancsToEuros(Number(ConversionValue))
        .toString();
    }else if (currentCurrency == "Knots"){
        resultMessage += KnotstoKph(Number(ConversionValue))
        .toString();
    }else{
        resultMessage = " Pay attention! That conversion is not supported.";
    }

 console.log(resultMessage);
}