knockout click handler

http://stackoverflow.com/questions/10332723/knockout-js-calling-functions-on-load

HTML

<script src="https://github.com/SteveSanderson/knockout/raw/master/build/output/knockout-latest.debug.js"></script>
<p>
    ID: <span data-bind="text: id"></span>
</p>
<div id="subscribe" data-bind="visible: isSubscribed == false">
    <button data-bind="click: SubscribeToCategory">Subscribe</button>
</div>
<div id="unsubscribe" data-bind="visible: isSubscribed == true">
    <button data-bind="click: UnsubscribeFromCategory">Unsubscribe</button>
</div>
<div>
    Category Name: <span data-bind="text: name"></span>Is Subscribed: <span data-bind="text: isSubscribed">
    </span>
</div>

JavaScript

var ViewModel = function(initialData) {
    var self = this;

    self.id = initialData;
    self.isSubscribed = ko.observable(false);
    self.name = ko.observable();

    self.SubscribeToCategory = function () {
        debugger;
        $.ajax({
            url: '@Url.Action("Subscribe", "Category")',
            type: 'POST',
            data: {
                categoryId: self.id
            },
            success: function () {
                self.isSubscribed(true);
            },
            failure: function () {
                self.isSubscribed(false);
            }
        });

        alert('Subscribing...');
    };

    self.UnsubscribeFromCategory = function () {
        $.ajax({
            url: '@Url.Action("Unsubscribe", "Category")',
            type: 'POST',
            data: {
                categoryId: self.id
            },
            success: function () {
                self.isSubscribed(false);
            },
            failure: function () {
                self.isSubscribed(true);
            }

        }); 

        alert('Unsubscribing...');
    };

    self.LoadCategory = function () {
        $.ajax({
            url: '@Url.Action("GetCategory", "Category")',
            type: 'POST',
            async: true,
            data: {
                categoryId: self.id
            },
            dataType: 'json',
            success: function (data) {
                self.isSubscribed(data.IsSubscribed);
                self.name(data.Name);
            }
        });
    };

    self.LoadCategory();
};


$(document).ready(function () {
    var data = '@Model';
    var viewModel = new ViewModel(data);
    ko.applyBindings(viewModel);
});