I am currently using the jQuery UI Datepicker script in order to display availability dates for a rental. I used the recommended way to feed the script am an array of disabled days but my problem is that the day rental ends should also be available as a start date for a new rental. The client asked for a red triangle on the first and last day to show it should be available. How can I achieve that with this plugin?

$(function() {
    <?php

    $date_range = array();
    $select = mysql_query("SELECT * FROM reservation WHERE cid='$chalet[id]' and status='1'");
    while ($r = mysql_fetch_array($select)) {
        $date_range1 = createDateRangeArray(date("Y-m-d", $r[arrive]), date("Y-m-d", $r[depart]));

        // How can i use those 2 arrays to detect the right triangle to display and make sure the day is selectable
        $first[] = reset($date_range1);
        $last[] = end($date_range1);

        $date_range = array_merge($date_range, $date_range1);
    }

    foreach ($date_range as $key => $values) {
        $dates .= '"' . $values . '", ';
    }
    if ($dates) {
        echo 'var disableddates = [' . substr($dates, 0, -2) . "];\n";
    } else {
        echo "var disableddates = [];\n";
    }

    ?>
    function DisableSpecificDates(date) {
        var string = jQuery.datepicker.formatDate('dd-mm-yy', date);
        return [disableddates.indexOf(string) == -1];
    }
    $( "#calendrier" ).datepicker({
        beforeShowDay: DisableSpecificDates
    });
});

The above code renders the following

:

I need it to look like this: