Javascript超时

每次我在沙箱环境中运行这段代码时，我都会超时并最终崩溃。我已经在多个IDE中运行了它，但仍然找不到任何语法错误。如果有人看到我没有看到的东西，我会非常感谢你的意见

//assign variables to memory
var carModel = new Array()
var milesDriven = new Array()
var gallonsUsed = new Array()
var milesperGallon = new Array()
var questionState, epaRating, conditionofVehicle, totalAverage;

var runningAverage = 0;
var i = 0;

do {
    //retrieve basic information about vehicle from standard input: model, miles, gallons
    carModel[i] = prompt("What type of vehicle do you drive?");
    milesDriven[i] = parseInt(prompt("How many miles have you 
                                   driven with this vehicle?"));
    gallonsUsed[i] = parseInt(prompt("How many gallons of gas have you used when driving this  vehicle?"));

    //calculate miles per gallon
    milesperGallon[i] = milesDriven[i] / gallonsUsed[i];
    runningAverage = runningAverage + milesperGallon[i];

    do {
        questionState = prompt("Do you have any more vehicles that you would like to enter? If yes, type 'yes'. If no, type 'no'.");
    } while (questionState != "yes" && questionState != "no");

    i++;
} while (questionState == "yes");

totalAverage = runningAverage / i;

// parse through each element of carModel, milesDriven, gallonsUsed
for (var j = 0; j <= i; j++) {
    //determine performance standards based upon M.P.G of vehicle
    if (milesperGallon[j] >= 38) {
        conditionofVehicle = "Good";
        epaRating = 10;
        //output the performance standards to user
        document.writeln("Your" + " " + carModel[j] + " " + "receives" + " " + milesperGallon[j] + " " + "miles per gallon.");
        document.writeln("Based upon this metric your vehicle is in" + " " + conditionofVehicle + " " + "condition and has a EPA rating of" + " " + epaRating + ".");
    } else if (milesperGallon[j] >= 31 && milesperGallon[j] < 38) {
        conditionofVehicle = "Good";
        epaRating = 9;
        //output the performance standards to user
        document.writeln("Your" + " " + carModel[j] + " " + "receives" + " " + milesperGallon[j] + " " + "miles per gallon.");
        document.writeln("Based upon this metric your vehicle is in" + " " + conditionofVehicle + " " + "condition and has a EPA rating of" + " " + epaRating + ".");
    } else if (milesperGallon[j] >= 27 && milesperGallon[j] < 31) {
        conditionofVehicle = "Good";
        epaRating = 8;
        //output the performance standards to user
        document.writeln("Your" + " " + carModel[j] + " " + "receives" + " " + milesperGallon[j] + " " + "miles per gallon.");
        document.writeln("Based upon this metric your vehicle is in" + " " + conditionofVehicle + " " + "condition and has a EPA rating of" + " " + epaRating + ".");
    } else if (milesperGallon[j] >= 23 && milesperGallon[j] < 27) {
        conditionofVehicle = "Fair";
        epaRating = 7;
        //output the performance standards to user
        document.writeln("Your" + " " + carModel[j] + " " + "receives" + " " + milesperGallon[j] + " " + "miles per gallon.");
        document.writeln("Based upon this metric your vehicle is in" + " " + conditionofVehicle + " " + "condition and has a EPA rating of" + " " + epaRating + ".");
    } else if (milesperGallon[j] >= 22 && milesperGallon[j] < 23) {
        conditionofVehicle = "Fair";
        epaRating = 6;
        //output the performance standards to user
        document.writeln("Your" + " " + carModel[j] + " " + "receives" + " " + milesperGallon[j] + " " + "miles per gallon.");
        document.writeln("Based upon this metric your vehicle is in" + " " + conditionofVehicle + " " + "condition and has a EPA rating of" + " " + epaRating + ".");
    } else if (milesperGallon[j] >= 19 && milesperGallon[j] < 22) {
        conditionofVehicle = "Fair";
        epaRating = 5;
        //output the performance standards to user
        document.writeln("Your" + " " + carModel[j] + " " + "receives" + " " + milesperGallon[j] + " " + "miles per gallon.");
        document.writeln("Based upon this metric your vehicle is in" + " " + conditionofVehicle + " " + "condition and has a EPA rating of" + " " + epaRating + ".");
    } else if (milesperGallon[j] >= 17 && milesperGallon[j] < 19) {
        conditionofVehicle = "Fair";
        epaRating = 4;
        //output the performance standards to user
        document.writeln("Your" + " " + carModel[j] + " " + "receives" + " " + milesperGallon[j] + " " + "miles per gallon.");
        document.writeln("Based upon this metric your vehicle is in" + " " + conditionofVehicle + " " + "condition and has a EPA rating of" + " " + epaRating + ".");
    } else if (milesperGallon[j] >= 15 && milesperGallon[j] < 17) {
        conditionofVehicle = "Bad";
        epaRating = 3;
        //output the performance standards to user
        document.writeln("Your" + " " + carModel[j] + " " + "receives" + " " + milesperGallon[j] + " " + "miles per gallon.");
        document.writeln("Based upon this metric your vehicle is in" + " " + conditionofVehicle + " " + "condition and has a EPA rating of" + " " + epaRating + ".");
    } else if (milesperGallon[j] >= 13 && milesperGallon[j] < 15) {
        conditionofVehicle = "Bad";
        epaRating = 2;
        //output the performance standards to user
        document.writeln("Your" + " " + carModel[j] + " " + "receives" + " " + milesperGallon[j] + " " + "miles per gallon.");
        document.writeln("Based upon this metric your vehicle is in" + " " + conditionofVehicle + " " + "condition and has a EPA rating of" + " " + epaRating + ".");
    } else if (milesperGallon[j] >= 0 && milesperGallon[j] < 13) {
        conditionofVehicle = "Bad";
        epaRating = 1;
        //output the performance standards to user
        document.writeln("Your" + " " + carModel[j] + " " + "receives" + " " + milesperGallon[j] + " " + "miles per gallon.");
        document.writeln("Based upon this metric your vehicle is in" + " " + conditionofVehicle + " " + "condition and has a EPA rating of" + " " + epaRating + ".");
    } else {
        document.writeln(" ");
    }
}
// check to make sure there is an input value
if (totalAverage >= 0) {
    document.writeln("You have" + " " + i + " " + "vehicles." + " " + "Between them      
                   they average" + " " + totalAverage + " " + "miles per gallon.");
}

//为内存分配变量
var carModel=新数组（）
var milesDriven=新数组（）
var gallonsUsed=新数组（）
var milesperGallon=新数组（）
var状态、分离、车辆状况、总平均值；
var runningAverage=0；
var i=0；
做{
//从标准输入中检索有关车辆的基本信息：型号、英里、加仑
carModel[i]=提示（“您驾驶哪种类型的车辆？”）；
milesdrive[i]=parseInt（提示（“您行驶了多少英里
用这辆车驾驶？）；
加仑消耗量[i]=parseInt（提示（“您驾驶此车辆时使用了多少加仑汽油？”）；
//计算每加仑英里数
milesperGallon[i]=行驶里程[i]/加仑[i]；
runningAverage=runningAverage+米力斯贝加隆[i]；
做{
questionState=提示（“您是否还有其他车辆要进入？如果有，请键入“是”。如果没有，请键入“否”。”；
}而（questionState！=“是”&&questionState！=“否”）；
i++；
}而（提问状态=“是”）；
totalAverage=runningAverage/i；
//解析carModel、milesDriven、gallonsUsed的每个元素
对于（变量j=0；j=38）{
车辆状况=“良好”；
epaating=10；
//将性能标准输出给用户
document.writeln（“您的“+”+carModel[j]+“+”接收“+”+milesperGallon[j]+“+”英里每加仑”）；
document.writeln（“根据此指标，您的车辆处于车辆+++”状态，且EPA评级为“++”+”）；
}else如果（米尔斯佩格隆[j]>=31&&米尔斯佩格隆[j]<38）{
车辆状况=“良好”；
epaating=9；
//将性能标准输出给用户
document.writeln（“您的“+”+carModel[j]+“+”接收“+”+milesperGallon[j]+“+”英里每加仑”）；
document.writeln（“根据此指标，您的车辆处于车辆+++”状态，且EPA评级为“++”+”）；
}else如果（米尔斯佩尔加隆[j]>=27和米尔斯佩尔加隆[j]<31）{
车辆状况=“良好”；
epaating=8；
//将性能标准输出给用户
document.writeln（“您的“+”+carModel[j]+“+”接收“+”+milesperGallon[j]+“+”英里每加仑”）；
document.writeln（“根据此指标，您的车辆处于车辆+++”状态，且EPA评级为“++”+”）；
}否则如果（米莱斯佩尔加隆[j]>=23&&米莱斯佩尔加隆[j]<27）{
车辆条件=“公平”；
epaating=7；
//将性能标准输出给用户
document.writeln（“您的“+”+carModel[j]+“+”接收“+”+milesperGallon[j]+“+”英里每加仑”）；
document.writeln（“根据此指标，您的车辆处于车辆+++”状态，且EPA评级为“++”+”）；
}else如果（米尔斯佩尔加隆[j]>=22和米尔斯佩尔加隆[j]<23）{
车辆条件=“公平”；
epaating=6；
//将性能标准输出给用户
document.writeln（“您的“+”+carModel[j]+“+”接收“+”+milesperGallon[j]+“+”英里每加仑”）；
document.writeln（“根据此指标，您的车辆处于车辆+++”状态，且EPA评级为“++”+”）；
}else如果（米尔斯佩尔加隆[j]>=19和米尔斯佩尔加隆[j]<22）{
车辆条件=“公平”；
分离=5；
//将性能标准输出给用户
document.writeln（“您的“+”+carModel[j]+“+”接收“+”+milesperGallon[j]+“+”英里每加仑”）；
document.writeln（“根据此指标，您的车辆处于车辆+++”状态，且EPA评级为“++”+”）；
}else如果（米尔斯佩尔加隆[j]>=17和米尔斯佩尔加隆[j]<19）{
车辆条件=“公平”；
epaating=4；
//将性能标准输出给用户
document.writeln（“您的“+”+carModel[j]+“+”接收“+”+milesperGallon[j]+“+”英里每加仑”）；
document.writeln（“根据此指标，您的车辆处于车辆+++”状态，且EPA评级为“++”+”）；
}else如果（米尔斯佩尔加隆[j]>=15和米尔斯佩尔加隆[j]<17）{
车辆状况=“坏”；
epaating=3；
//将性能标准输出给用户
document.writeln（“您的“+”+carModel[j]+“+”接收“+”+milesperGallon[j]+“+”英里每加仑”）；
document.writeln（“根据此指标，您的车辆处于车辆+++”状态，且EPA评级为“++”+”）；
}否则如果（米尔斯佩格隆[j]>=13&&米尔斯佩格隆[j]<15）{
车辆状况=“坏”；
epaating=2；
//将性能标准输出给用户
document.writeln（“您的“+”+carModel[j]+“+”接收“+”+milesperGallon[j]+“+”英里每加仑”）；
document.writeln（“根据此指标，您的车辆处于车辆+++”状态，且EPA评级为“++”+”）；
}else如果（milesperGallon[j]>=0&&milesperGallon[j]<13）{
车辆状况=“坏”；
分离=1；
//将性能标准输出给用户
document.writeln（“您的“+”+carModel[j]+“+”接收“+”+milesperGallon[j]+“+”英里每加仑”）；
document.writeln（“根据此指标，您的车辆
milesDriven[i] = parseInt(prompt("How many miles have you 
                               driven with this vehicle?"));

milesDriven[i] = parseInt(prompt("How many miles have you driven with this vehicle?"));

if (totalAverage >= 0) {
    document.writeln("You have" + " " + i + " " + "vehicles." + " " + "Between them      
                   they average" + " " + totalAverage + " " + "miles per gallon.");
}

if (totalAverage >= 0) {
    document.writeln("You have" + " " + i + " " + "vehicles." + " " + "Between them they average" + " " + totalAverage + " " + "miles per gallon.");
}