function check_date(str)
{
	months=new Array();
	months[1]=31;months[2]=28;months[3]=31;months[4]=30;
	months[5]=31;months[6]=30;months[7]=31;months[8]=31;
	months[9]=30;months[10]=31;months[11]=30;months[12]=31;
	
	//message="Unacceptable date format (dd-mm-yyyy)";
	
	var field = str.value;
	
	while (field.indexOf('/')>=0)
		field = field.replace('/', "-");
						
	//var field = str.value;
	//str.value =field;
	
	if (str.value=="")
		return(false);
	else
	{
		comp=field.split('-');

		if ( (field.indexOf('-')<0) || (comp.length!=3) || (isNaN(comp[2])) || (isNaN(comp[1])) || (isNaN(comp[0])) || (comp[1]<1)||(comp[1]>12) )
			return(false);
		
		if (comp[2].length==2)
			comp[2] = "20" + comp[2];
			
		if (months[comp[1]]<comp[0])
		{
			 
			if ((comp[1]==2)&&(comp[0]==29))
			{  
				if ( (comp[2]%400==0) || ( (comp[2]%4==0) && (comp[2]%100!=0) ) ) //->disekto
					return(comp[0] + "-" + comp[1] + "-" + comp[2]);
			}
			return(false);
		}
		if (comp[2].length!=4)
			return(false);
	
		if ((comp[2]<2009)||(comp[2]>2040)){
			alert("Year is out of range: should be between 2009 and 20240");
			return(false);
		}
		
		return(comp[0] + "-" + comp[1] + "-" + comp[2] );
		
	}
}
	
function date_comparison(date1, date2)
{		
	dt1 = date1.split("-");
	dt2 = date2.split("-");
	
	if ( (dt1[0]==dt2[0]) && (dt1[1]==dt2[1]) && (dt1[2]==dt2[2]) )	//an idies imerominies
		return 0;	//equal
	if (dt1[2] > dt2[2])
		return 1;
	else if (dt1[2] < dt2[2])
		return 2;
	else	//idia eti
	{
		if (dt1[1] > dt2[1])
			return 1;
		else if (dt1[1] < dt2[1])
			return 2;
		else 	//idioi mines (kai idia eti)
		{
			if (dt1[0] > dt2[0])
				return 1;
			else
				return 2;
		}
	}
	
	return -1;
}


function sub_dates(date1, date2)
{
	var date1_arr = date1.split("-");
	var date2_arr = date2.split("-");
	
	var dt1 = new Date(date1_arr[2], date1_arr[1]-1, date1_arr[0]);	//Month is 0-11 in JavaScript
	var dt2 = new Date(date2_arr[2], date2_arr[1]-1, date2_arr[0]);	//Month is 0-11 in JavaScript
	
	//Set 1 day in milliseconds
	var one_day=1000*60*60*24
	
	var res = Math.ceil( (dt2.getTime()-dt1.getTime())/(one_day) );
	
	return (res);
	/*
	//Set the two dates
	today=new Date()
	var christmas=new Date(today.getFullYear(), 11, 25) //Month is 0-11 in JavaScript
	if (today.getMonth()==11 && today.getDate()>25) //if Christmas has passed already
	christmas.setFullYear(christmas.getFullYear()+1) //calculate next year's Christmas
	//Set 1 day in milliseconds
	var one_day=1000*60*60*24
	
	//Calculate difference btw the two dates, and convert to days
	document.write(Math.ceil((christmas.getTime()-today.getTime())/(one_day))+
	" days left until Christmas!")*/
}
	
function next_day(dt1, dt2)
{
	document.getElementById(dt2).value = document.getElementById(dt1).value;
}