DateTimePicker restricting from date

HTML

<script src="https://github.com/SteveSanderson/knockout/raw/master/build/output/knockout-latest.debug.js"></script>
<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.11/themes/base/jquery-ui.css">
<div class="ui-widget-content">Start Date:</div>
<div class="ui-widget-content">        
   <input id="from" data-bind="datepicker: StartDate, datepickerOptions: { numberOfMonths:2, defaultDate: -14 }" />
     &nbsp;<span data-bind="text:StartDate"> </span>
</div>
<div class="ui-widget-content">End Date:</div>
<div class="ui-widget-content">
  <input id="to" data-bind="datepicker: EndDate, datepickerOptions: { numberOfMonths:2 }" />        
     &nbsp;<span data-bind="text:EndDate"> </span>
</div>

JavaScript

ko.bindingHandlers.datepicker = {
    init: function(element, valueAccessor, allBindingsAccessor) {
        //initialize datepicker with some optional options
        var options = allBindingsAccessor().datepickerOptions || {};

        // Start of comment to make it work              
        options.onSelect = function(selectedDate) {
            var option = this.id == "from" ? "minDate" : "maxDate",
                instance = $(this).data("datepicker"),
                date = $.datepicker.parseDate(
                instance.settings.dateFormat || $.datepicker._defaults.dateFormat, selectedDate, instance.settings);
            var dates = $("#from, #to");
            dates.not(this).datepicker("option", option, date);
            valueAccessor()(date);
        };

        // End of Comment to make it work
        $(element).datepicker(options);

        //handle the field changing
        ko.utils.registerEventHandler(element, "change", function() {
            var observable = valueAccessor();
            observable($(element).datepicker("getDate"));
        });

        //handle disposal (if KO removes by the template binding)
        ko.utils.domNodeDisposal.addDisposeCallback(element, function() {
            $(element).datepicker("destroy");
        });

    },
    update: function(element, valueAccessor) {
        var value = ko.utils.unwrapObservable(valueAccessor()),
            current = $(element).datepicker("getDate");

        if (value - current !== 0) {
            $(element).datepicker("setDate", value);
        }
    }
};

var viewModel = {
    StartDate: ko.observable(),
    EndDate: ko.observable(),
};

ko.applyBindings(viewModel);