var isNav4 = false, isNav5 = false, isIE4 = false
var strSeperator = "/"; 
var vDateType = 3;
var vYearType = 4;
var vYearLength = 4;
var err = 0;
if (navigator.appName == "Netscape") {
	if (navigator.appVersion < "5") {
		isNav4 = true;
		isNav5 = false;
	}
else if (navigator.appVersion > "4") {
		isNav4 = false;
		isNav5 = true;
	}
}
else {
	isIE4 = true;
}

function DateFormat(vDateName, vDateValue, e, dateCheck, dateType) {
	vDateType = dateType;
	if (vDateValue == "~") {
		alert("AppVersion = "+navigator.appVersion+" \nNav. 4 Version = "+isNav4+" \nNav. 5 Version = "+isNav5+" \nIE Version = "+isIE4+" \nYear Type = "+vYearType+" \nDate Type = "+vDateType+" \nSeparator = "+strSeperator);
		vDateName.value = "";
		vDateName.focus();
		return true;
	}
	var whichCode = (window.Event) ? e.which : e.keyCode;
	if (vDateValue.length > 8 && (isNav4 || isNav5)) {
		if ((vDateValue.indexOf("-") >= 1) || (vDateValue.indexOf("/") >= 1)) return true;
	}
	var alphaCheck = " abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ/-";
	if (alphaCheck.indexOf(vDateValue) >= 1) {
		if (isNav4) {
			vDateName.value = "";
			vDateName.focus();
			vDateName.select();
			return false;
		}
		else {
			vDateName.value = vDateName.value.substr(0, (vDateValue.length-1));
			return false;
		}
	}
	if (whichCode == 8) return false;
	else {
		var strCheck = '47,48,49,50,51,52,53,54,55,56,57,58,59,95,96,97,98,99,100,101,102,103,104,105';
		if (strCheck.indexOf(whichCode) != -1) {
			if (isNav4) {
				if (((vDateValue.length < 6 && dateCheck) || (vDateValue.length == 7 && dateCheck)) && (vDateValue.length >=1)) {
					alert("Invalid date\nPlease re-enter");
					vDateName.value = "";
					vDateName.focus();
					vDateName.select();
					return false;
				}
				if (vDateValue.length == 6 && dateCheck) {
					var mDay = vDateName.value.substr(2,2);
					var mMonth = vDateName.value.substr(0,2);
					var mYear = vDateName.value.substr(4,4)
					if (mYear.length == 2 && vYearType == 4) {
						var mToday = new Date();
						var checkYear = mToday.getFullYear() + 30;
						var mCheckYear = '20' + mYear;
						if (mCheckYear >= checkYear) mYear = '19' + mYear;
						else mYear = '20' + mYear;
					}
					var vDateValueCheck = mMonth+strSeperator+mDay+strSeperator+mYear;
					if (!dateValid(vDateValueCheck)) {
						alert("Invalid date\nPlease re-enter");
						vDateName.value = "";
						vDateName.focus();
						vDateName.select();
						return false;
					}
					return true;
				}
				else {
					if (vDateValue.length >= 8  && dateCheck) {
						if (vDateType == 1) {
							var mDay = vDateName.value.substr(2,2);
							var mMonth = vDateName.value.substr(0,2);
							var mYear = vDateName.value.substr(4,4)
							vDateName.value = mMonth+strSeperator+mDay+strSeperator+mYear;
						}
						if (vDateType == 2) {
							var mYear = vDateName.value.substr(0,4)
							var mMonth = vDateName.value.substr(4,2);
							var mDay = vDateName.value.substr(6,2);
							vDateName.value = mYear+strSeperator+mMonth+strSeperator+mDay;
						}
						if (vDateType == 3) {
							var mMonth = vDateName.value.substr(2,2);
							var mDay = vDateName.value.substr(0,2);
							var mYear = vDateName.value.substr(4,4)
							vDateName.value = mDay+strSeperator+mMonth+strSeperator+mYear;
						}
						var vDateTypeTemp = vDateType;
						vDateType = 1;
						var vDateValueCheck = mMonth+strSeperator+mDay+strSeperator+mYear;
						if (!dateValid(vDateValueCheck)) {
							alert("Invalid date\nPlease re-enter");
							vDateType = vDateTypeTemp;
							vDateName.value = "";
							vDateName.focus();
							vDateName.select();
							return false;
						}
						vDateType = vDateTypeTemp;
						return true;
					}
					else {
						if (((vDateValue.length < 8 && dateCheck) || (vDateValue.length == 9 && dateCheck)) && (vDateValue.length >=1)) {
							alert("Invalid date\nPlease re-enter");
							vDateName.value = "";
							vDateName.focus();
							vDateName.select();
							return false;
						}
					}
				}
			}
			else {
				if (((vDateValue.length < 8 && dateCheck) || (vDateValue.length == 9 && dateCheck)) && (vDateValue.length >=1)) {
					alert("Invalid date\nPlease re-enter");
					vDateName.value = "";
					vDateName.focus();
					return true;
				}
				if (vDateValue.length >= 8 && dateCheck) {
					if (vDateType == 1) {
						var mMonth = vDateName.value.substr(0,2);
						var mDay = vDateName.value.substr(3,2);
						var mYear = vDateName.value.substr(6,4)
					}
					if (vDateType == 2) {
						var mYear = vDateName.value.substr(0,4)
						var mMonth = vDateName.value.substr(5,2);
						var mDay = vDateName.value.substr(8,2);
					}
					if (vDateType == 3) {
						var mDay = vDateName.value.substr(0,2);
						var mMonth = vDateName.value.substr(3,2);
						var mYear = vDateName.value.substr(6,4)
					}
					if (vYearLength == 4) {
						if (mYear.length < 4) {
							alert("Invalid date\nPlease re-enter");
							vDateName.value = "";
							vDateName.focus();
							return true;
						}
					}
					var vDateTypeTemp = vDateType;
					vDateType = 1;
					var vDateValueCheck = mMonth+strSeperator+mDay+strSeperator+mYear;
					if (mYear.length == 2 && vYearType == 4 && dateCheck) {
						var mToday = new Date();
						var checkYear = mToday.getFullYear() + 30; 
						var mCheckYear = '20' + mYear;
						if (mCheckYear >= checkYear) mYear = '19' + mYear;
						else mYear = '20' + mYear;
						vDateValueCheck = mMonth+strSeperator+mDay+strSeperator+mYear;
						if (vDateTypeTemp == 1) vDateName.value = mMonth+strSeperator+mDay+strSeperator+mYear;
						if (vDateTypeTemp == 3) vDateName.value = mDay+strSeperator+mMonth+strSeperator+mYear;
					} 
					if (!dateValid(vDateValueCheck)) {
						alert("Invalid date\nPlease re-enter");
						vDateType = vDateTypeTemp;
						vDateName.value = "";
						vDateName.focus();
						return true;
					}
					vDateType = vDateTypeTemp;
					return true;
				}
				else {
					if (vDateType == 1) {
						if (vDateValue.length == 2) {
							vDateName.value = vDateValue+strSeperator;
						}
						if (vDateValue.length == 5) {
							vDateName.value = vDateValue+strSeperator;
						}
					}
					if (vDateType == 2) {
						if (vDateValue.length == 4) {
							vDateName.value = vDateValue+strSeperator;
						}
						if (vDateValue.length == 7) {
							vDateName.value = vDateValue+strSeperator;
						}
					} 
					if (vDateType == 3) {
						if (vDateValue.length == 2) {
							vDateName.value = vDateValue+strSeperator;
						}
						if (vDateValue.length == 5) {
							vDateName.value = vDateValue+strSeperator;
						}
					}
					return true;
				}
			}
			if (vDateValue.length == 10 && dateCheck) {
				if (!dateValid(vDateName, vDateName)) {
					alert("Invalid date\nPlease re-enter");
					vDateName.focus();
					vDateName.select();
				}
			}
			return false;
		}
		else {
			if (isNav4) {
				vDateName.value = "";
				vDateName.focus();
				vDateName.select();
				return false;
			}
			else {
				vDateName.value = vDateName.value.substr(0, (vDateValue.length-1));
				return false;
			}
		}
	}
}

function dateValid(objName) {
	var strDate;
	var strDateArray;
	var strDay;
	var strMonth;
	var strYear;
	var intday;
	var intMonth;
	var intYear;
	var booFound = false;
	var datefield = objName;
	var strSeparatorArray = new Array("-"," ","/",".");
	var intElementNr;
	var strMonthArray = new Array(12);
	strMonthArray[0] = "Jan";
	strMonthArray[1] = "Feb";
	strMonthArray[2] = "Mar";
	strMonthArray[3] = "Apr";
	strMonthArray[4] = "May";
	strMonthArray[5] = "Jun";
	strMonthArray[6] = "Jul";
	strMonthArray[7] = "Aug";
	strMonthArray[8] = "Sep";
	strMonthArray[9] = "Oct";
	strMonthArray[10] = "Nov";
	strMonthArray[11] = "Dec";
	strDate = objName;
	if (strDate.length < 1) {
		return true;
	}
	for (intElementNr = 0; intElementNr < strSeparatorArray.length; intElementNr++) {
		if (strDate.indexOf(strSeparatorArray[intElementNr]) != -1) {
			strDateArray = strDate.split(strSeparatorArray[intElementNr]);
			if (strDateArray.length != 3) {
				err = 1;
				return false;
			}
			else {
				strDay = strDateArray[0];
				strMonth = strDateArray[1];
				strYear = strDateArray[2];
			}
			booFound = true;
		}
	}
	if (booFound == false) {
		if (strDate.length > 5) {
			strDay = strDate.substr(0, 2);
			strMonth = strDate.substr(2, 2);
			strYear = strDate.substr(4);
		}
	}
	if (strYear.length == 2) {
		strYear = '20' + strYear;
	}
	strTemp = strDay;
	strDay = strMonth;
	strMonth = strTemp;
	intday = parseInt(strDay, 10);
	if (isNaN(intday)) {
		err = 2;
		return false;
	}
	intMonth = parseInt(strMonth, 10);
	if (isNaN(intMonth)) {
		for (i = 0; i < 12; i++) {
			if (strMonth.toUpperCase() == strMonthArray[i].toUpperCase()) {
				intMonth = i + 1;
				strMonth = strMonthArray[i];
				i = 12;
			}
		}
		if (isNaN(intMonth)) {
			err = 3;
			return false;
		}
	}
	intYear = parseInt(strYear, 10);
	if (isNaN(intYear)) {
		err = 4;
		return false;
	}
	if (intMonth > 12 || intMonth < 1) {
		err = 5;
		return false;
	}
	if ((intMonth == 1 || intMonth == 3 || intMonth == 5 || intMonth == 7 || intMonth == 8 || intMonth == 10 || intMonth == 12) && (intday > 31 || intday < 1)) {
		err = 6;
		return false;
	}
	if ((intMonth == 4 || intMonth == 6 || intMonth == 9 || intMonth == 11) && (intday > 30 || intday < 1)) {
		err = 7;
		return false;
	}
	if (intMonth == 2) {
		if (intday < 1) {
			err = 8;
			return false;
		}
		if (LeapYear(intYear) == true) {
			if (intday > 29) {
				err = 9;
				return false;
			}
		}
		else {
			if (intday > 28) {
				err = 10;
				return false;
			}
		}
	}
	return true;
}

function LeapYear(intYear) {
	if (intYear % 100 == 0) {
		if (intYear % 400 == 0) { return true; }
	}
	else {
		if ((intYear % 4) == 0) { return true; }
	}
	return false;
}