JavaScript 多次打印

Question

你好，我想让用户输入一些分数，最后给出最高分和最低分，但出于某种原因，它打印了两次，第二次打印了无穷大和想法？

    var gradeAwarded;
var gradeAwarded;
var repeate = true;
var max;
var A;
var B;
var C;
var F;

var repeat, studentArr = [], markArr = [];
while (repeat !== 'n' && repeat !== 'N'){
    studentArr.push(prompt("Enter Student Name: "));
    markArr.push(parseInt (prompt("Enter Student mark: ")));
    repeat = prompt ("Do you want to enter another student: y/n");
}  

Array.prototype.max = function() {
  return Math.max.apply(Math, markArr);
};

Array.prototype.min = function() {
  return Math.min.apply(Math, markArr);
};
var min = markArr.min();
var max = markArr.max();


if (markArr <0 || markArr >100){
    alert("Grate out of bounds");
}else if (markArr >= 83){
    gradeAwarded = "A";
    A = +1;
}else if (markArr >= 70){
    gradeAwarded = "B";
    B = +1;
}else if (markArr >= 50){
    gradeAwarded = "C";
    C = +1; 
}else if (markArr >= 0){
    gradeAwarded = "F";
    F = +1;                                                     
}

    document.write("The Highest mark was : "+max);
    document.write("The Lowest mark was : "+min);

Answer 1

必须是||而不是 &&

while (repeat !== 'n' || repeat !== 'N'){
    studentArr.push(prompt("Enter Student Name: "));
    markArr.push(parseInt (prompt("Enter Student mark: ")));
    repeat = prompt ("Do you want to enter another student: y/n");
}

并且您还应该清除或将null设置为重复过程中的变量