function GenerateDateCombination(frmname,selyearname,selmonthname,seldatename,beginyear,endyear,theyear,themonth,thedate){

	//Parameters		Description

	//-------------------------------------------------------------------------------------------------

	//frmname		:	Required , The name of form where the selectbox belong .		
	//selyearname	:	Required , The selectbox's name of year part .
	//selmonthname	:	Required , The selectbox's name of month part .
	//seldatename	:	Required , The selectbox's name of date part .
	//beginyear		:	Optional , The start year of the selectbox's year part , if omitted , default is 10 years less then this year .
	//endyear		:	Optional , The end year of the selectbox's year part , if omitted , default is 10 years more then this year .
	//theyear		:	Optional , The default selected year you wished , if omitted , default is this year .
	//themonth		:	Optional , The default selected month you wished , if omitted , default is this month .
	//thedate		:	Optional , The default selected date you wished , if omitted , default is today .

	if(!frmname||!selyearname||!selmonthname||!seldatename){	//If not specify the form name ,and each select box's name .
		document.write('參數不完整，請檢查 FormName , Year Select Name , Month Select Name , Date Select Name');
		return false;
	}
	
	if(beginyear&&!isNaN(beginyear))parseInt(beginyear)<0?0:beginyear;
	else beginyear=false;

	if(endyear&&!isNaN(endyear))parseInt(endyear)<0?0:endyear;
	else endyear=false;

	if(theyear&&!isNaN(theyear))parseInt(theyear)<0?0:theyear;
	else theyear=false;
	
	if(themonth&&!isNaN(themonth)){
		if(parseInt(themonth)<1){
			themonth=1;
		}
		else if(parseInt(themonth)>12){
			themonth=parseInt(themonth)%12
			themonth=0?1:themonth;
		}
	}
	else themonth=false;

	if(thedate&&!isNaN(thedate)){
		if(parseInt(thedate)<1){
			thedate=1;
		}
		else if(parseInt(thedate)>31){
			thedate=determinedate(theyear,themonth);
		}
	}
	else thedate=false;

	var today=new Date();									//Create object today
	var yyyy=(theyear)?theyear:today.getFullYear();			//Get the current year
	var mm=(themonth)?themonth:today.getMonth()+1;			//Get the current month
	var dd=(thedate)?thedate:today.getDate();				//Get the current date
	var bgnyr=(beginyear)?beginyear:1996;
	var endyr=(endyear)?endyear:today.getFullYear()+1;

	if(bgnyr>endyr){
		var tempyr=bgnyr;
		bgnyr=endyr;
		endyr=tempyr;
	}

	if(yyyy<bgnyr||yyyy>endyr)yyyy=bgnyr;

	var yrsel;
	var mnsel;
	var daysel;

	//************ The year select box contains this year to 10 years later ****************

	yrsel='<select name='+selyearname+' onchange=\'switchthedays("'+frmname+'","'+selyearname+'","'+selmonthname+'","'+seldatename+'")\'>';
	for(i=bgnyr;i<=endyr;i++){
		if(i==yyyy)yrsel=yrsel+'<option value='+i+' selected>'+i+'</option>';
		else yrsel=yrsel+'<option value='+i+'>'+i+'</option>';
	}
	yrsel=yrsel+'</select>';

	//************ The month select box contains 12 months and this month was default selected ****************

	mnsel='<select name='+selmonthname+' onchange=\'switchthedays("'+frmname+'","'+selyearname+'","'+selmonthname+'","'+seldatename+'")\'>';
	for(i=1;i<=12;i++){
		if(i==mm)mnsel=mnsel+'<option value='+i+' selected>'+i+'</option>';
		else mnsel=mnsel+'<option value='+i+'>'+i+'</option>';
	}
	mnsel=mnsel+'</select>';

	//************ The data select box contains the days taht depends on *******************
	//************ this year and this month and today was default selected ****************

	daysel='<select name='+seldatename+'>';
	for(i=1;i<=determinedate(yyyy,mm);i++){
		if(i==dd)daysel=daysel+'<option value='+i+' selected>'+i+'</option>';
		else daysel=daysel+'<option value='+i+'>'+i+'</option>';
	}
	daysel=daysel+'</select>';

	//*************** Show in the document *********************

	document.write (yrsel+' 年 '+mnsel+' 月 '+daysel+' 日');
}

//************ To determine whether this year is bissextile and  *******
//************ how many days should this month contains ****************


function determinedate(yearvalue,monthvalue){
	switch(monthvalue){
		case 2:
			if(yearvalue%400==0 || (yearvalue%4==0 && yearvalue%100!=0))days=29;	//29 days in bissextile February 
			else days=28;
			break;
		case 4:
		case 6:
		case 9:
		case 11:
			days=30;
			break;
		default:
			days=31;
	}
	return days;
}

//************ Change the contents of the date select box *****************

function switchthedays(frmname,selyearname,selmonthname,seldatename){

	var today=new Date();				//Create object today
	var dd=today.getDate();				//Get the current date
	var objmonth=eval('document.'+frmname+'.'+selmonthname+'.value');
	var objyear=eval('document.'+frmname+'.'+selyearname+'.value');
	var objdaysel=eval('document.'+frmname+'.'+seldatename);

	objdaysel.length=determinedate(parseInt(objyear),parseInt(objmonth));
	for(i=0;i<objdaysel.length;i++){
		objdaysel.options[i].value=i+1;
		objdaysel.options[i].text=i+1;
		if(i==dd-1)objdaysel.options[i].selected=true;
	}
}