我在 html 表单中使用 4 个下拉列表。2 个下拉菜单代表活动的开始和结束月份，另外 2 个代表活动的开始和结束年份。我允许用户输入 3 年的历史记录，完成后，我提示用户转到下一部分。为了计算 3 年的历史记录，我计算了开始月份和结束月份之间的差值，并且每次都将其输入到计数器中（请注意，我使用的是数字而不是 Date 对象）。这些值被传递到我的数组中，但计数器没有更新。它只是被数组中的新值替换。谁能告诉我问题出在哪里？这是我的代码：
var arrMonthStarted = []; //It stores the month that activity started
var arrMonthEnded = []; //It stores the month that activity ended
var arrYearStarted = []; //It stores the year that activity started
var arrYearEnded = []; //It stores the year that activity ended
function validatedropdowns1(){
var monthStarted = document.getElementById('idMonthStarted').value;
var yearStarted = document.getElementById('idYearStarted').value;
var monthEnded = document.getElementById('idMonthEnded').value;
var yearEnded = document.getElementById('idYearEnded').value;
arrMonthStarted.push(monthStarted);
arrMonthEnded.push(monthEnded);
arrYearStarted.push(yearStarted);
arrYearEnded.push(yearEnded);
//Calculating the 3-year history
var count = 0;
if(yearStarted == yearEnded){
if(monthEnded < monthStarted){
var temp = monthEnded;
monthEnded = monthStarted;
monthStarted = temp;
}
var diffmonths = monthEnded - monthStarted;
count = count + diffmonths;
}
//Take the difference between the years.
var subYears = yearEnded - yearStarted;
//If 1, just take the difference on the first 2 lines of the calendar
if(subYears == 1){
var subLine1 = 12 - monthStarted;
var subLine2 = 12 - monthEnded;
var finalLine2 = 12 - subLine2;
var takeresult = subLine1 + finalLine2;
count = count + takeresult;
}
//Follow case 1, but also add 12 months
if(subYears == 2){
var subLine3 = 12 - monthStarted;
var subLine4 = 12 - monthEnded;
var finalLine3 = 12 - subLine4;
var takeresult11 = subLine3 + finalLine4;
var takeresult1 = 12 + takeresult11;
count = count + takeresult1l;
}
//add another 12 months (24 now) on step 1.
if(subYears == 3){
var subLine5 = 12 - monthStarted;
var subLine6 = 12 - monthEnded;
var finalLine5 = 12 - subLine6;
var takeresult22 = subLine5 + finalLine6;
var takeresult2 = 24 + takeresult22;
count = count + takeresult2;
}
var arrCount = []; // array to hold the count var
arrCount.push(count); // push count into arrCount
//print total months
for(var m = 0; m < arrCount.length; m++){
alert("The array now has" + "" + "" + count + "" + "months");
}
if(arrCount == 36){
alert("You have successfuly finished this section. Please go to the next section. Thank you.")
document.getElementById('btnAdd').disable = true;
}
if(arrMonthEnded[arrMonthEnded.length - 1] - arrMonthStarted[arrMonthSarted.length] > 1){
alert("There should not be a gap of more than a month in your 3 year activity. Fill in all the months and select from the list what you were doing each month. Thank you.")
}
}
另外，我试图测试结束日期和下一个开始日期之间的差距。例如，如果我输入 12 2011 作为结束日期，并输入 03 2012 作为下一个开始日期，我想看看是否有超过一个月的差距。我尝试了下面的代码，但它没有工作
if(arrMonthEnded[arrMonthEnded.length - 1] - arrMonthStarted[arrMonthSarted.length] > 1){
alert("There should not be a gap of more than a month in your 3 year activity. Fill in all the months and select from the list what you were doing each month. Thank you.")
}
提前感谢您（KSFIDDLE http://jsfiddle.net/k4dNb/）