knockoutjs databind with jquery controls

http://stackoverflow.com/questions/6399078/knockoutjs-databind-with-jquery-controls

HTML

<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.11/themes/base/jquery-ui.css">
<script src="https://cdnjs.cloudflare.com/ajax/libs/knockout/3.3.0/knockout-min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/knockout.mapping/2.4.1/knockout.mapping.min.js"></script>
<input data-bind="datepicker: myDate, datepickerOptions: options" />

<hr />

<button data-bind="click: setToCurrentDate">Set To Current Date</button>
<button data-bind="click: changeMinDate">Change min date</button>

<hr />

<div data-bind="text: myDate"></div>

CSS

td, th { padding: 5px; border: solid 1px black; }
th { color: #666; }
a { font-size: .75em; }

JavaScript

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

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

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

        // subscribe to all changes in the options object
        ko.computed(function(){
            var options = ko.mapping.toJS(opts) || {};

            for (var i in options)
                $el.datepicker('option', i, options[i]);
        });
    },
    update: function(element, valueAccessor) {
        var value = ko.utils.unwrapObservable(valueAccessor()),
            $el = $(element),
            current = $el.datepicker("getDate");
        
        if (value - current !== 0) {
            $el.datepicker("setDate", value);   
        }
    }
};

var viewModel = {
    myDate: ko.observable(new Date("12/01/2013")),
    setToCurrentDate: function() {
        this.myDate(new Date());
    },
    options: {
        minDate: ko.observable(new Date())
    },
    changeMinDate: function(){
        this.options.minDate(new Date('01/01/2015'));
    }
};

ko.applyBindings(viewModel);