SO - 15400775

HTML

<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.9.2/themes/redmond/jquery-ui.css">
<script src="http://ajax.googleapis.com/ajax/libs/jqueryui/1.9.2/jquery-ui.min.js"></script>
<input id='from' type='text' placeholder='from' />

<input id='to' type='text' placeholder='to'/>

<input id='clear' type="button" value="Clear Selection" />

JavaScript

var array = ["2018-09-22","2015-03-15","2015-03-16"]

var _selectedDay = "";
var _cascadeDisabled = false;

$('#from').datepicker({
    beforeShowDay: function(date) {
        var _date = jQuery.datepicker.formatDate('yy-mm-dd', date);
        var _isDisabledDate = array.indexOf(_date) != -1;      
        
        return [ array.indexOf(_date) == -1 ]
    },
    onClose: function(dateStr, event) {
        _selectedDay = dateStr;
    }
});

$('#to').datepicker({
    beforeShowDay: function(date) {
        var _date = jQuery.datepicker.formatDate('yy-mm-dd', date);
        var _isDisabledDate = array.indexOf(_date) != -1;
        if(_selectedDay.length && _isDisabledDate 
          && _selectedDay < _date) {
            _cascadeDisabled = true;
        }
        
        if(_cascadeDisabled) return false;
        
        return [ array.indexOf(_date) == -1 ]
    },
    onClose: function(dateStr, event) {
        _cascadeDisabled = false;
    }
});


$("#clear").click(function() {
    $("input[type='text']").val("");
});