JavaScript month-day linkage to achieve the core code _ time and date

Copy Code code as follows:

var startyear = 1980;
var endyear = 2500;

function Monthandday ()
{
THIS.INITDDL = function (objyear,objmonth,objday,hidyear,hidmonth,hidday)
{
This.init (Objyear,objmonth,objday,hidyear,hidmonth,hidday);
This. Selectchange (Objyear,objmonth,objday,hidyear,hidmonth,hidday);
}

This.init = function (objyear,objmonth,objday,hidyear,hidmonth,hidday)
{
var year = document.getElementById (objyear);
var month = document.getElementById (objmonth);
var day = document.getElementById (Objday);
var me=this;

if (year.length = 1)
{
Year.options[0] = new Option ("Unlimited", "");
for (var i = StartYear i < endyear; i++)
{
Year.options[year.length] = new Option (i,i);
}
}
Me.yearoptionschange (Document.all[objyear].value,objyear,objmonth,objday);
Me.monthoptionschange (Document.all[objyear].value,document.getelementbyid (objmonth). Value,objDay);
}

This.yearoptionschange = function (selectvalue,objyear,objmonth,objday)
{
var month = document.getElementById (objmonth);
var day = document.getElementById (Objday);
var me=this;
month.length = 0;
day.length = 0;
Month.options[0]=new Option ("Unlimited", "");
Day.options[0]=new Option ("Unlimited", "");

if (Selectvalue = "")
{
return;
}

for (var i = 1; i < i++)
{
Month.options[month.length] = new Option (i < 10? ("0" + i): i), i);
}
Me.monthoptionschange (document.getElementById (objyear). Value,document.getelementbyid (ObjMonth). Value,objDay);
}

This.monthoptionschange = function (yearselectvalue,monthselectvalue,objday)
{
var day = document.getElementById (Objday);
var endday;
day.length = 0;

Day.options[0]=new Option ("Unlimited", "");

if (Monthselectvalue = "")
{
Return
}
if ((parseint (yearselectvalue)% 400 = 0) | | (parseint (yearselectvalue)% 4 = 0 && parseint (yearselectvalue)% 100!= 0))
{
if (parseint (monthselectvalue) = = "2")
{
Endday = 29;
}
}
Else
{
if (parseint (monthselectvalue) = = "2")
{
Endday = 28;
}
}
Switch (parseint (monthselectvalue))
{
Case 1:
Case 3:
Case 5:
Case 7:
Case 8:
Case 10:
Case 12:
Endday = 31;
Break
Case 4:
Case 6:
Case 9:
Case 11:
Endday = 30;
Break
}

for (var i = 1; I <= endday; i++)
{
Day.options[day.length] = new Option (i < 10? ("0" + i): i), i);
}
}

This. Selectchange = function (objyear,objmonth,objday,hidyear,hidmonth,hidday)
{
var year = Document.all[objyear];
var month = Document.all[objmonth];
var day = Document.all[objday];
var me = this;

Year.onchange = function ()
{
Me.yearoptionschange (This.options[this.selectedindex].value,objyear,objmonth,objday);
Document.all[hidyear].value = This.options[this.selectedindex].value;
Document.all[hidmonth].value = "";
Document.all[hidday].value = "";
}

Month.onchange = function ()
{
Me.monthoptionschange (Document.all[hidyear].value,this.options[this.selectedindex].value,objday);
Document.all[hidmonth].value = This.options[this.selectedindex].value;
Document.all[hidday].value = "";
}

Day.onchange = function ()
{
Document.all[hidday].value = Day.selectvalue;
}
}
}