var min_year=2000; // defines lowest year in year menu
var max_year=2021; // defines highest year in the year menu
var weekday_showing=false; // make this false to prevent the weekday element from being displayed
var dayofweek_returned_as_number=false; // make this true to make dayofweek return a number (0-6)
var month_returned_as_number=true; // make this true to make month return a number (0-11)

if(min_year <= 400)
  alert("Minimum year must be higher than 400 for this algorithm to work.");
	
// The following code adds three methods to the built-in Date object
function _strMonth(){
  var months=new Array("January","February","March","April","May","June","July","August","September","October","November","December");
  return months[this.getMonth()];
}

function _strDay(){
  var days=new Array("Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday");
  return days[this.getDay()];
}

function _weekOf(){
  sunday=((arguments[0]==null) || (!arguments[0])); // Check for optional argument
  return (new Date(this - ((this.getDay() - ((sunday) ? 0 : 1)) *24*60*60*1000)));
}

// Add these methods to all dates
Date.prototype.weekOf= _weekOf;
Date.prototype.strMonth= _strMonth;
Date.prototype.strDay= _strDay;

function changeDays(numb,date_form,aname){
  MonthCtrl=eval("date_form." + aname +"month");
  DayCtrl=eval("date_form." + aname +"day");
  YearCtrl=eval("date_form." + aname +"year");

  mth=eval(MonthCtrl.selectedIndex);
  sel=eval(YearCtrl.selectedIndex);
  yr=eval(YearCtrl.options[sel].text);

  if(numb!=1){
    numDays=numDaysIn(mth,yr);
    eval("date_form." + aname +"day.options.length="+numDays);
    for(i=27;i<numDays;i++){
      j=i+1;
      eval("date_form." + aname +"day.options["+i+"].text = "+j);
    }
  }
}
	
function numDaysIn(mth,yr){
  if(mth==3 || mth==5 || mth==8 || mth==10) return 30;
  else if ((mth==1) && leapYear(yr)) return 29;
  else if (mth==1) return 28;
  else return 31;
}

function leapYear(yr){
  if(((yr % 4 == 0) && yr % 100 != 0) || yr % 400 == 0)
    return true;
  else
    return false;
}

function arr(){
  this.length=arr.arguments.length;
  for(n=0;n<arr.arguments.length;n++){
    this[n]=arr.arguments[n];
  }
}

var cur=new Date();

function getWeekDay(mth,day,yr){
  first_day=firstDayOfYear(yr);
  for(num=0;num>mth;num++){
    first_day += numDaysIn(num,yr);
  }
  first_day += day-1;
  return first_day%7;
}

function firstDayOfYear(yr){
  diff=yr - 401;
  return parseInt((1 + diff + (diff / 4) - (diff / 100) + (diff / 400)) % 7);
}

// fixes a Netscape 2 and 3 bug
function getFullYear(d){ // d is a date object
  yr=d.getYear();
  if(yr<1000)
    yr+=1900;
  return yr;
}

function datedrop(myname,feeddate){
  //alert (feeddate);
  if(!feeddate){
    d=new Date();
    edmonth=d.getMonth();
    edday=d.getDate();
    edyear=d.getFullYear();
  }else{
    d=new Date(feeddate)
    edmonth=d.getMonth();
    edday=d.getDate();
    edyear=d.getFullYear();
  }
  // write month element
	
  document.write("<select name="+myname+"month size=1 onChange='changeDays(0,this.form,"+'"'+myname+'"'+")' class=\"textoscampos\">");
  for(i=1;i<13;i++)
    document.write("<option"+(month_returned_as_number?" value="+i:"")+(edmonth==i-1?" selected":"")+">"+months[i-1]+"\n");
  // write day element
  document.write("</select><select name="+myname+"day size=1 onChange='changeDays(0,this.form,"+'"'+myname+'"'+")' class=\"textoscampos\">\n");
  for(i=1;i<=numDaysIn(d.getMonth(),getFullYear(d));i++)
    document.write("<option"+(edday==i?" selected":"")+">"+i+"\n");
  // write year element
  document.write("</select><select name="+myname+"year size=1 onChange='changeDays(0,this.form,"+'"'+myname+'"'+")' class=\"textoscampos\">\n");
  for(i=min_year;i<max_year;i++)
    document.write("<option"+(edyear==i?" selected":"")+">"+i+"\n");
  document.write("</select>");
}

function datedropa(myname,feeddate,text){
  //alert (feeddate);
  if(!feeddate){
    d=new Date();
    edmonth=d.getMonth();
    edday=d.getDate();
    edyear=d.getFullYear();
  }else{
    d=new Date(feeddate)
    edmonth=d.getMonth();
    edday=d.getDate();
    edyear=d.getFullYear();
  }
	
  // write year element
  document.write("<select name=\""+myname+"\" size=1 >\n");
  document.write(" <option value=\"0\">" + text + "\n");
  for(i=min_year;i<=max_year;i++)
    for(j=1;j<13;j++)
      document.write("<option value=\"" + j + "/" + i + "\">"+ months[j-1].substr(0,3) +"/" + i+"\n");
  document.write("</select>");
}

function datedropd(myname,feeddate,text){
  //alert (feeddate);
  if(!feeddate){
    d=new Date();
    edmonth=d.getMonth();
    edday=d.getDate();
    edyear=d.getFullYear();
  }else{
    d=new Date(feeddate)
    edmonth=d.getMonth();
    edday=d.getDate();
    edyear=d.getFullYear();
  }
	
  // write year element
  document.write("<select name=\""+myname+"\" size=1 >\n");
  document.write(" <option value=\"0\">" + text + "\n");
  for(i=max_year;i>=min_year;i--)
    for(j=12;j>=1;j--)
      document.write("<option value=\"" + j + "/" + i + "\">" + months[j-1].substr(0,3) + "/" + i +"\n");
  document.write("</select>");
}