function validateDateTime(element, fieldName) {
                try {
                    jQuery.datepicker.parseDate('mm/dd/yy', element.val());
                    clearErrorField(element);
                    setErrorMessage("");
                    return true;
                } catch (e) {
                    setErrorField(element);
                    setErrorMessage("Field '" + fieldName + "' must be in format: 'mm/dd/yyyy'");
                    return false;
                }
            }

            function validateDateTime(element, fieldName, errorField) {
                try {
                    jQuery.datepicker.parseDate('mm/dd/yy', element.val());
                    clearErrorField(element);
                    setErrorMessage("", errorField);
                    return true;
                } catch (e) {
                    setErrorField(element);
                    setErrorMessage("Field '" + fieldName + "' must be in format: 'mm/dd/yyyy'", errorField);
                    return false;
                }
            }

function compareDate(date1, date2) {
    if (date1.getYear() > date2.getYear())
        return 1;
    else if (date1.getYear() < date2.getYear())
        return -1;
    else if (date1.getMonth() > date2.getMonth())
        return 1;
    else if (date1.getMonth() < date2.getMonth())
        return -1;
    else if (date1.getDate() > date2.getDate())
        return 1;
    else if (date1.getDate() < date2.getDate())
        return -1;
    else return 0;
}

function validateDateTimeRange(element, minDate, errorMessage) {
    var cDate = jQuery.datepicker.parseDate('mm/dd/yy', element.val());    
    if (compareDate(cDate, minDate) >= 0) {
        clearErrorField(element);
        setErrorMessage("");
        return true;
    }
    else {
        setErrorField(element);
        setErrorMessage(errorMessage);
        return false;
    }
}
function validateDateTimeRange(element, minDate, errorMessage, errorField) {
    var cDate = jQuery.datepicker.parseDate('mm/dd/yy', element.val());
    if (compareDate(cDate, minDate) >= 0) {
        clearErrorField(element);
        setErrorMessage("", errorField);
        return true;
    }
    else {
        setErrorField(element);
        setErrorMessage(errorMessage, errorField);
        return false;
    }
}
            function setErrorMessage(message) {
                $('#errorMessage').text(message);
            }

            function setErrorMessage(message, id) {
                $(id).text(message);
            }
            
            function setErrorField(field) {
                field.focus();
                field.addClass('wrong_field');
            }

            function clearErrorField(field) {
                field.removeClass('wrong_field');
            }

            function is_int(value) {
                if ((parseFloat(value) == parseInt(value)) && !isNaN(value)) {
                    return true;
                } else {
                    return false;
                }
            }
            
            // Check if string is a valid email address
            function regIsEmail(fData){
                var reg = new RegExp("^[0-9a-zA-Z]+@[0-9a-zA-Z]+[\.]{1}[0-9a-zA-Z]+[\.]?[0-9a-zA-Z]+$");
                  return reg.test(fData);
            }

            function validateEmail() {
                var email = $('#email').val();
                if (!regIsEmail(email)) {
                    setErrorField($('#email'));
                    setErrorMessage('Please enter a valid email address');
                    return false;
                }
                clearErrorField($('#email'));
                setErrorMessage("");
                return true;
            }

            function validateEmail(errorField) {
                var email = $('#email').val();
                if (!regIsEmail(email)) {
                    setErrorField($('#email'));
                    setErrorMessage('Please enter a valid email address', errorField);
                    return false;
                }
                clearErrorField($('#email'));
                setErrorMessage("", errorField);
                return true;
            }

            function validateNumber(field, fieldName, min, max) {
                if (!is_int(field.val())) {
                    setErrorField(field);
                    setErrorMessage("Field '" + fieldName + "' must be a valid number");
                    return false;
                }
                var value = parseInt(field.val());
                if (value < min) {
                    setErrorField(field);
                    setErrorMessage("Field '" + fieldName + "' must greater than " + (min - 1));
                    return false;
                }
                if (value > max) {
                    setErrorField(field);
                    setErrorMessage("Field '" + fieldName + "' must lower than " + max);
                    return false;
                }

                clearErrorField(field);
                setErrorMessage("");
                return true;
            }

            function validateNumber(field, fieldName, min, max, errorField) {
                if (!is_int(field.val())) {
                    setErrorField(field);
                    setErrorMessage("Field '" + fieldName + "' must be a valid number", errorField);
                    return false;
                }
                var value = parseInt(field.val());
                if (value < min) {
                    setErrorField(field);
                    setErrorMessage("Field '" + fieldName + "' must greater than " + (min - 1), errorField);
                    return false;
                }
                if (value > max) {
                    setErrorField(field);
                    setErrorMessage("Field '" + fieldName + "' must lower than " + max, errorField);
                    return false;
                }

                clearErrorField(field);
                setErrorMessage("", errorField);
                return true;
            }

            function validateStep1() {
                if (!validateDateTime($('#start-date'), "From")) return false;
                if (!validateDateTime($('#end-date'), "To")) return false;
                if (!validateDateTimeRange($('#start-date'), new Date(), "Start date must greater than Today")) return false;
                if (!validateDateTimeRange($('#end-date'), new Date($('#start-date').val()), "End date must greater than start date")) return false;

                if (!validateNumber($('#nPerson'), "Number Of Person", 1, 100)) return false;
                if (!validateNumber($('#nRoom'), "Number Of Room", 1, 100)) return false;

                setErrorMessage("");
                return true;
            }
            function validateStep2() {
                if (!validateName()) return false;
                if (!validateEmail()) return false;
                
                setErrorMessage("");
                return true;
            }
            
            function validateName() {
                if (isEmpty($('#userName').val())) {
                    setErrorField($('#userName'));
                    setErrorMessage("Please enter your name.");
                    return false;
                }
                clearErrorField($('#userName'));
                setErrorMessage("");
                return true;
            }

            // check 0-9 digit
function regIsDigit(fData)
{
    var reg = new RegExp("^[+- 0-9]$");
    return (reg.test(fData));
}

function isEmpty(str) {
    return (str == null) || (str.length == 0);
}