Knockout checkbox and radio

HTML

<script src="http://rniemeyer.github.com/KnockMeOut/Scripts/knockout-latest.debug.js"></script>
 <header>
    <a href="#" id="toggle-button" data-bind="click:function(){toggle(!toggle())}">
      <img src="https://cdn.xl.thumbs.canstockphoto.com/canstock33334848.jpg" data-bind="css: {rotated : toggle() }">
    </a>
  </header>

  <main id="wrapper" data-bind="css: {'menu-visible' : toggle() }">

    <aside id="sidebar-wrapper">
      <div></div>
    </aside>

    <section id="page-content-wrapper">
      <div id="map"></div>
    </section>

  </main>

JavaScript

var viewModel = {
toggle : ko.observable(false)
}

ko.applyBindings(viewModel);