function validateDate(date) {
    try {
		var shortMonths = [4, 6, 9, 11];
		var day = 1;
		var month = 1;
		var year = 1;

        if(date.length === 10) {
			var splitString = date.split(".");
			for(var i = 0; i < splitString.length; i++) {
				var number = parseInt(splitString[i], 10);

				switch(i) {
					case 0:
						day = number;
						break;
					case 1:
						month = number;
						break;
					default:
						year = number;
						break;
				}
			}
			
			if(month > 0 && month < 13) {
				if(month === 2) {
					var isLeapYear = year % 4 === 0 && year % 100 !== 0 || year % 400 === 0;

					if(isLeapYear) {
						return day > 0 && day < 30;
					} else {
						return day > 0 && day < 29;
					}
				}

				if(shortMonths.includes(month)) {
					return day > 0 && day < 31;
				} else {
					return day > 0 && day < 32;
				}
			}

			return false;
        }

        return false;
    } catch (exception) {
	    console.log("Fehler bei validateDate: " + exception);
		return false;
    }
}

function doValidation(elementToValidate) {
    var obj = $(elementToValidate);

    var isValid = validateDate(obj.val());

    obj.css("color", (isValid ? "#555" : "red"));

    return isValid;
}

function validateTime(time) {
    try {
        var numberString = time.replace("[^0-9]", "");

		if (numberString.length < 3) {
			if (numberString.length < 2) {
				numberString = "0" + numberString;
			}

			while (numberString.length < 4) {
				numberString = numberString + "0";
			}
		} else {
			while (numberString.length < 4) {
				numberString = "0" + numberString;
			}
		}

		if (numberString.length > 4) {
			numberString = numberString.substring(0, 5);
		}

		var hours = parseInt(numberString.substring(0, 2), 10);
		var minutes = parseInt(numberString.substring(3, 5), 10);

        return Number.isInteger(hours) && Number.isInteger(minutes) && hours >= 0 && hours < 25 && minutes >= 0 && minutes < 60;
    } catch (exception) {
		console.log("Fehler bei validateTime: " + exception);
		return false;
	}
}

function doTimeValidation(elementToValidate) {
	console.log("Rufe doTimeValidation auf...");

	var obj = $(elementToValidate);

	var timeString = obj.val();
	
	if (timeString.length === 0) {
		timeString = "0000";
    }

    var isValid = validateTime(timeString);

    obj.css("color", (isValid ? "#555" : "red"));

    return isValid;
}