JavaScript代码不断重复语句。我怎样才能阻止这一切？

我正在创建一个为期12天的圣诞节javascript程序，当我打印出该语句时，它会不断重复该语句。你能给我一些关于如何解决这个问题并使程序正常工作的建议吗

var day = ["first", "second", "third", "fourth", "fifth", "sixth", 
"seventh", "eighth", "ninth", "tenth", "eleventh", "twelfth"];
var song = "";

for (var x = 0; x <= 13; x++) {
song += "On the " + day[x] + " day of Christmas";
song += " my true love gave to me: ";

if (x == 0) {
    song += "a partridge in a pear tree."
} 
else {
    switch (x) {
        case 12:
            song += ("twelve drummers drumming, ");
        case 11:
            song += ("eleven pipers piping, ");
        case 10:
            song += ("ten lords a-leping, ");
        case 9:
            song += ("nine ladies dancing, ");
        case 8:
            song += ("eight maids a-milking, ");
        case 7:
            song += ("seven swans a-swimming, ");
        case 6:
            song += ("six geese a-laying, ");
        case 5:
            song += ("five gold rings,");
        case 4:
            song += ("four calling birds, ");
        case 3:
            song += ("three french hens, ");
        case 2:
            song += ("two turtle doves ");
        case 1:
            song += ("and a partridge in a pear tree.");
            break;
    }
}
console.log(song);}

var-day=[“第一”、“第二”、“第三”、“第四”、“第五”、“第六”，
“第七”、“第八”、“第九”、“第十”、“第十一”、“第十二”]；
var song=“”；
for（var x=0；xbreak语句在切换情况下丢失

switch (x) {
        case 12:
            song += ("twelve drummers drumming, ");
            break;
        case 11:
            song += ("eleven pipers piping, ");
            break;
        case 10:
            song += ("ten lords a-leping, ");
            break;
        case 9:
            song += ("nine ladies dancing, ");
            break;
        case 8:
            song += ("eight maids a-milking, ");
            break;
        case 7:
            song += ("seven swans a-swimming, ");
            break;
        case 6:
            song += ("six geese a-laying, ");
            break;
        case 5:
            song += ("five gold rings,");
            break;
        case 4:
            song += ("four calling birds, ");
            break;
        case 3:
            song += ("three french hens, ");
            break;
        case 2:
            song += ("two turtle doves ");
            break;
        case 1:
            song += ("and a partridge in a pear tree.");
            break;
    }

在switch语句中，您遗漏了
break
语句。此外，您可以将
x==0
大小写放在开关本身上，不需要单独的if语句。
switch语句要求在大小写中有一个break，并且在循环开始时，song变量需要设置为空，开关也需要设置为cases需要从零开始，以便每次都能得到正确的大小写：

for (var x = 0; x < 12; x++) {
    song = "";    
    song += "On the " + day[x] + " day of Christmas";
    song += " my true love gave to me: ";

    if (x == 0) {
        song += "a partridge in a pear tree."
    } 
    else {
        switch (x) {
            case 11:
                song += ("twelve drummers drumming, ");
                break;
            case 10:
                song += ("eleven pipers piping, ");
                break;
            case 9:
                song += ("ten lords a-leping, ");
                break;
            case 8:
                song += ("nine ladies dancing, ");
                break;
            case 7:
                song += ("eight maids a-milking, ");
                break;
            case 6:
                song += ("seven swans a-swimming, ");
                break;
            case 5:
                song += ("six geese a-laying, ");
                break;
            case 4:
                song += ("five gold rings,");
                break;
            case 3:
                song += ("four calling birds, ");
                break;
            case 2:
                song += ("three french hens, ");
                break;
            case 1:
                song += ("two turtle doves ");
                break;
            case 0:
                song += ("and a partridge in a pear tree.");
                break;
            default:
        }
    }
    console.log(song);
}

for（变量x=0；x<12；x++）{
宋=“”；
歌曲+=“在”+日[x]+“圣诞节”；
歌曲+=“我的真爱给了我：”；
如果（x==0）{
歌曲+=“梨树上的鹧鸪。”
} 
否则{
开关（x）{
案例11：
歌曲+=（“十二鼓手鼓声”）；
打破
案例10：
歌曲+=（“十一管风笛”）；
打破
案例9：
宋+=（“十大领主阿乐平”）；
打破
案例8：
歌曲+=（“九位女士跳舞”）；
打破
案例7：
歌曲+=（“八个女佣挤奶”）；
打破
案例6：
歌曲+=（“七只天鹅a-游泳”）；
打破
案例5：
宋+=（“六只鹅产蛋”）；
打破
案例4：
宋+=（“五枚金戒指”）；
打破
案例3：
歌+=（“四只鸣叫的鸟”）；
打破
案例2：
宋+=（“三只法国母鸡”）；
打破
案例1：
宋+=（“两只斑鸠”）；
打破
案例0：
歌+=（“和梨树上的鹧鸪”）；
打破
违约：
}
}
console.log（歌曲）；
}
var-day=[“第一”、“第二”、“第三”、“第四”、“第五”、“第六”，
“第七”、“第八”、“第九”、“第十”、“第十一”、“第十二”]；
var dayMessages=[“梨树上的一只鹧鸪”，“梨树上的一只鹧鸪”，“两只斑鸠”，“三只法国母鸡”，“四只鸣叫的鸟”，“五枚金戒指”，“六只下蛋的鹅，”，
“七只天鹅a游泳”，“八个女佣a挤奶”，“十个领主a乐平”，“十个领主a乐平”，“十一个风笛手吹笛”，“十二个鼓手鼓乐，”；
var song=“”；
对于（var x=0；x），您可以为您的开关大小写字符串创建和等效的数组，并删除开关大小写，然后从该数组中使用
var day = ["first", "second", "third", "fourth", "fifth", "sixth", 
"seventh", "eighth", "ninth", "tenth", "eleventh", "twelfth"];
var dayMessages = ["a partridge in a pear tree.", "and a partridge in a pear tree.", "two turtle doves ", "three french hens, ", "four calling birds, ", "five gold rings,", "six geese a-laying, ", 
"seven swans a-swimming, ", "eight maids a-milking, ", "ten lords a-leping, ", "ten lords a-leping, ", "eleven pipers piping, ", "twelve drummers drumming, "];
var song = "";

for (var x = 0; x <= 13; x++) {
  song = "On the " + day[x] + " day of Christmas";
  song += " my true love gave to me: ";
  song += dayMessages[x];

  console.log(song);
}