Javascript:While循环不会停止 - 转换单位以给出空间面积

Question

由于某种原因，这段代码不断循环。目的是将平方英尺或米转换为另一种测量单位。我希望代码循环并仅在用户不输入“米”或“英尺”一词时再次提示用户，而是无限循环并导致 chrome 崩溃。我究竟做错了什么？谢谢!

while (whichunit !== "meter" || "foot"){
var whichunit = prompt("Would you like to convert from square meter or square foot? Enter meter/foot below");

    if(whichunit == "meter"){
    var unitnum = prompt("What is the price per meter?");
    var matchboxindex = unitnum * 0.0015;
    console.log("The match box index is " + matchboxindex);
}
        else if(whichunit == "foot"){
        var unitnum = prompt("What is the price per foot?");
        var matchboxindex = unitnum *0.0015 * 10.7639;
        console.log("The match box index is " + matchboxindex);
        }
            else {
            console.log("Please enter either foot or meter");
            }
}

Answer 1

while (whichunit !== "meter" || "foot"){
var whichunit = prompt("Would you like to convert from square meter or square     foot? Enter meter/foot below");

无限循环是因为'||'后面的条件(应该是“&”)只是“foot”，它的计算结果始终为 true。所以只需重写为:

var whichunit = '';
while (whichunit !== "meter" && whichunit !== "foot"){
    whichunit = prompt("Would you like to convert from square meter or square     foot? Enter meter/foot below");
    ...