// date field validation (called by other validation functions that specify minYear/maxYear)

function isDate(minYear,maxYear,minDays,maxDays) {

	var inputStr = gField.value

	// convert hyphen delimiters to slashes

	while (inputStr.indexOf("-") != -1) {

		inputStr = replaceString(inputStr,"-","/")

	}

	var delim1 = inputStr.indexOf("/")

	var delim2 = inputStr.lastIndexOf("/")

	if (delim1 != -1 && delim1 == delim2) {

		// there is only one delimiter in the string

		alert("The date entry is not in an acceptable format.\n\nYou can enter dates in the following formats: mmddyyyy, mm/dd/yyyy, or mm-dd-yyyy.  (If the month or date data is not available, enter \'01\' in the appropriate location.)")

		gField.focus()

		gField.select()

		return false

	}

	if (delim1 != -1) {

		// there are delimiters; extract component values

		var mm = parseInt(inputStr.substring(0,delim1),10)

		var dd = parseInt(inputStr.substring(delim1 + 1,delim2),10)

		var yyyy = parseInt(inputStr.substring(delim2 + 1, inputStr.length),10)

	} else {

		// there are no delimiters; extract component values

		var mm = parseInt(inputStr.substring(0,2),10)

		var dd = parseInt(inputStr.substring(2,4),10)

		var yyyy = parseInt(inputStr.substring(4,inputStr.length),10)

	}

	if (isNaN(mm) || isNaN(dd) || isNaN(yyyy)) {

		// there is a non-numeric character in one of the component values

		alert("The date entry is not in an acceptable format.\n\nYou can enter dates in the following formats: mmddyyyy, mm/dd/yyyy, or mm-dd-yyyy.")

		gField.focus()

		gField.select()

		return false

	}

	if (mm < 1 || mm > 12) {

		// month value is not 1 thru 12

		alert("Months must be entered between the range of 01 (January) and 12 (December).")

		gField.focus()

		gField.select()

		return false

	}

	if (dd < 1 || dd > 31) {

		// date value is not 1 thru 31

		alert("Days must be entered between the range of 01 and a maximum of 31 (depending on the month and year).")

		gField.focus()

		gField.select()

		return false

	}



	// validate year, allowing for checks between year ranges

	// passed as parameters from other validation functions

	if (yyyy < 100) {

		// entered value is two digits, which we allow for 1930-2029

		if (yyyy >= 30) {

			yyyy += 1900

		} else {

			yyyy += 2000

		}

	}



	var today = new Date()

	if (!minYear) {

		// function called with specific day range parameters

		var dateStr = new String(monthDayFormat(mm) + "/" + monthDayFormat(dd) + "/" + yyyy)

		var testDate = new Date(dateStr)

		if (testDate.getTime() < (today.getTime() + (minDays * 24 * 60 * 60 * 1000))) {

			alert("The most likely range for this entry begins " + minDays + " days from today.")

		}

		if (testDate.getTime() > today.getTime() + (maxDays * 24 * 60 * 60 * 1000)) {

			alert("The most likely range for this entry ends " + maxDays + " days from today.")

		}

	} else if (minYear && maxYear) {

		// function called with specific year range parameters

		if (yyyy < minYear || yyyy > maxYear) {

			// entered year is outside of range passed from calling function

			alert("The most likely range for this entry is between the years " + minYear + " and " + maxYear + ".  If your source data indicates a date outside this range, then enter that date.")

		}

	} else {

		// default year range (now set to (this year - 100) and (this year + 25)

		var thisYear = today.getYear()

		if (thisYear < 100) {

			thisYear += 1900

		}

		if (yyyy < minYear || yyyy > maxYear) {

			alert("It is unusual for a date entry to be before " + minYear + " or after " + maxYear + ". Please verify this entry.")

		}

	}

	if (!checkMonthLength(mm,dd)) {

		gField.focus()

		gField.select()

		return false

	}

	if (mm == 2) {

		if (!checkLeapMonth(mm,dd,yyyy)) {

			gField.focus()

			gField.select()

			return false

		}

	}

	// put the Informix-friendly format back into the field

	gField.value = monthDayFormat(mm) + "/" + monthDayFormat(dd) + "/" + yyyy

	return true

}