Regarding a Date Picker in php/javascript

I have a javascript jquery date picker which, at the minute only allows you to select days based on days in a database, as well as only allowing you to select the current day (if it isnt in the database as a holiday). Weekends are also disabled.

What i'm trying to do now is only allow the user to select a day from database +1 on date picker.

I've obviously pulled out the latest date entered into my database and plus'd one to it, so this is the date i only want to be available to select... But what if the next day is a disabled day from the other Holiday dates? which way can i get around this and actually only displaying one? AND having a condition on my holiday dates?

My javascript jquery date picker atm:

 <script type="text/javascript">

     //  Holiday Dates
    var unavailableDates = 
[<?php 

while($date = mysqli_fetch_assoc($execute)) {

        //  Populating javascript array with the dates from database
        echo '"' . $date = date('Y-n-j', strtotime($date['holiday_date'])) . '"';

        //  Adding a comma in array
    if ( $i < $number) {
                    echo ',';
    }
    $i ++;
}
    ?>
    ];

//  Entered Dates
var unavailableEnteredDates = 
[<?php 

while($dateEntered = mysqli_fetch_assoc($executeQuery)) {
    //  Populating javascript array with the dates from database
    echo '"' . $dateEntered = date('Y-n-j', strtotime($dateEntered['totalsDate'])) . '"';

    //  Adding a comma in array
    if ( $y < $number2) {
        echo ',';
    }
    $y ++;
}
?>
];

//  Concatenented array of 2 above
var allUnavailableDates = unavailableDates.concat(unavailableEnteredDates);

    //  Sets the no weekends and specified holiday dates
   function noWeekendsOrHolidays(date) {
    var noWeekend = jQuery.datepicker.noWeekends(date);
    return noWeekend[0] ? holidays(date) : noWeekend;
}

//  Gets the holidays
function holidays(date) {
    dmy = date.getFullYear() + "-" + (date.getMonth() + 1) + "-" + date.getDate();
    if ($.inArray(dmy, allUnavailableDates) == -1) {
        return [true, ""];
    } else {
        return [false, "", "Holiday Date"];
    }

}

//  Setting up the Date Picker
$(function() {
    $("#datepickerUser").datepicker({
        dateFormat: 'yy-m-d',
        beforeShowDay: noWeekendsOrHolidays,
        maxDate: "+0d"
    });
    $(function() { ("#testButton").datepicker("show") });

});

My solution i came up with:

          //    Adding one to the day so we can display this
      $latestPlusOne = date('Y-n-j', strtotime( "$latestDate + 1 day" ));
      $availableTakingDate;

        //  This for loop will loop through the size of the array
        //  Each time it finds the date inside the array it will plus 1 to the date
        //  Otherwise, break out of the loop and the new date var will be an available one
for ($i = 0; $i <= count($dateArray); $i++) {
    if (in_array($latestPlusOne, $dateArray)) {

        $latestPlusOne = date('Y-n-j', strtotime( "$latestPlusOne + 1 day" ));
    } else {
        $availableTakingDate = $latestPlusOne;
        break;
    }
}
?>


<script type="text/javascript">

    //  Date :: wanted available
    var availableDate = <?php echo json_encode($availableTakingDate); ?>;

function displayDate(date) {
    dmy = date.getFullYear() + "-" + (date.getMonth() +1) + "-" + date.getDate();

    if (dmy == availableDate) {
        return [true, ""];

    } else {
        return [false, ""];
    }
}

//  Setting up the Date Picker
$(function() {
    $("#datepickerUser").datepicker({
        dateFormat: 'yy-m-d',
        beforeShowDay: displayDate,
        maxDate: "+0d"
    });
    $(function() { ("#testButton").datepicker("show") });

});