function isdate (ldate)
	{			
		i=0;		
		while (i < ldate.length)
		{
			if (ldate.charAt(i) == '/')	break;
			i++;
		}
		ls_dd_pos = i;
		ls_dd_value = ldate.substring(0,ls_dd_pos);		
		
		ldate = ldate.substring(ls_dd_pos + 1,ldate.length);
		i=0;
		while (i < ldate.length)
		{
			if (ldate.charAt(i) == '/')	break;
			i++;
		}
		ls_mm_pos = i;
		ls_mm_value = ldate.substring(0,ls_mm_pos);		
		
		ldate = ldate.substring(ls_mm_pos + 1,ldate.length);
		i=0
		while (i < ldate.length)
		{
			if (ldate.charAt(i) == '/')	break;
			i++;
		}
		ls_yy_pos = i;
		ls_yy_value = ldate.substring(0,ls_yy_pos);			
					
		ls_msg = "Λάθος στην ημερομηνία. Η ημερομηνία πρέπει να έχει τη μορφή: HH/MM/EEEE";
		if ((!Number(ls_mm_value)) || (!Number(ls_dd_value)) || (!Number(ls_yy_value))) return ls_msg;		
		if ((ls_mm_value < 0) || (ls_dd_value < 0) || (ls_yy_value < 0)) return ls_msg;
		if ((ls_mm_value > 12) || (ls_yy_value < 2000) || (ls_dd_value > 31)) return ls_msg;
		if ((ls_dd_value == 31) && (!((ls_mm_value == 1) || (ls_mm_value == 3) || (ls_mm_value == 5) || (ls_mm_value == 7) || (ls_mm_value == 8) || (ls_mm_value == 10) || (ls_mm_value == 12)))) return ls_msg;		
		if ((ls_dd_value > 29) && (ls_mm_value == 2)) return ls_msg;		
		if ((ls_dd_value == 29) && (ls_mm_value == 2) && (ls_yy_value % 4 != 0)) return ls_msg;		
				
		return '';
		
	}
	
	function isinteger (li_int)
	{	
		var ls = new String(li_int);
		var li = new String('0');
			
		i=0; comma=0;
		while (i < li_int.length)
		{
			dg = li_int.charAt(i);
			if (!((dg == '0') ||(dg == '1') ||(dg == '2') ||(dg == '3') ||(dg == '4') ||(dg == '5') ||(dg == '6') ||(dg == '7') ||(dg == '8') ||(dg == '9') ||(dg == '-'))) 
			{
				 
				 if (!((dg == ',') || (dg == '.')))
					break;
				 else
					comma++;
			}
			if (comma == 0) li = li + dg;
			i++;
		}
		if (comma > 1) return -1;
		if (i < ls.length) return -1;
		ls = ls.replace(",", ".");
		if (!Number(ls)) return -1;
		ln = new Number(ls);
		li2 =  new Number(li);			
		if (ls < 2) return -2;			
		if (li2 - ln != 0 ) return -3
		return 1;			
	}
	
	function isint (li_int)
	{	
		var ls = new String(li_int);
		var li = new String('0');
			
		i=0; comma=0;
		while (i < li_int.length)
		{
			dg = li_int.charAt(i);
			if (!((dg == '0') ||(dg == '1') ||(dg == '2') ||(dg == '3') ||(dg == '4') ||(dg == '5') ||(dg == '6') ||(dg == '7') ||(dg == '8') ||(dg == '9') )) 
			{
				 
				 if (!((dg == ',') || (dg == '.')))
					break;
				 else
					comma++;
			}
			if (comma == 0) li = li + dg;
			i++;
		}
		if (comma > 0) return -1;
		if (i < ls.length) return -1;		
		if (!Number(ls)) return -1;		
		return 1;			
	}

	function check_int_length (li_int, len)
	{				
		i=0;
		while (i < li_int.length)
		{
			dg = li_int.charAt(i);
			if (!((dg == '0') ||(dg == '1') ||(dg == '2') ||(dg == '3') ||(dg == '4') ||(dg == '5') ||(dg == '6') ||(dg == '7') ||(dg == '8') ||(dg == '9') )) 
			{	
				break;
			}			
			i++;
		}
		if (i == len) 
			return 1;
		else 
			return -1;
	}
		
	function isamount (ld_amount)
	{	
		var ls = new String(ld_amount);
		var i = 0;
		var comma = 0;	
		var decdg = 0;	
		
		while (i < ld_amount.length)
		{			
			dg = ld_amount.charAt(i);				
			if (!((dg == '0') ||(dg == '1') ||(dg == '2') ||(dg == '3') ||(dg == '4') ||(dg == '5') ||(dg == '6') ||(dg == '7') ||(dg == '8') ||(dg == '9') ||(dg == '-'))) 
			{
				 if (!(dg == ','))
					break;
				 else				 
					comma = comma + 1;				 
			}
			if (comma > 0) decdg++ ;
			i = i + 1;
		}
		
		if ((comma > 1) || (decdg-1> 2)) return -3;		
		if (i < ld_amount.length) return -1		
		ls = ls.replace(",", ".");		
		if (!Number(ls)) return -3;						
		if (ls <= 0) return -3;		
		return 1;	
	
	}
	
	function compare_numbers (a, b)
	{
		var la = new String(a);
		var lb = new String(b);
		
		la = la.replace(",", ".");
		lb = lb.replace(",", ".");
		na = new Number(la);
		nb = new Number(lb);				

		if ( ( na - nb > 0 ) && ( nb > 0 ) )
			return true;
		else
			return false;		
	}
	
	function datetostring (ldate)
	{	
		var ls_date;
				
		i=0;		
		while (i < ldate.length)
		{
			if (ldate.charAt(i) == '/')	break;
			i++;
		}
		ls_dd_pos = i;
		ls_dd_value = ldate.substring(0,ls_dd_pos);		
		
		ldate = ldate.substring(ls_dd_pos + 1,ldate.length);
		i=0;
		while (i < ldate.length)
		{
			if (ldate.charAt(i) == '/')	break;
			i++;
		}
		ls_mm_pos = i;
		ls_mm_value = ldate.substring(0,ls_mm_pos);		
		
		ldate = ldate.substring(ls_mm_pos + 1,ldate.length);
		i=0
		while (i < ldate.length)
		{
			if (ldate.charAt(i) == '/')	break;
			i++;
		}
		ls_yy_pos = i;
		ls_yy_value = ldate.substring(0,ls_yy_pos);			
					
		ls_date = ls_yy_value + '/' + ls_mm_value + '/' + ls_dd_value;
				
		return ls_date;
		
	}