learning_jquery/Chapter 3/03.js

$(document).ready(function () {
  'use strict';

  $('#switcher')
    .hover(
      function () { $(this).addClass('hover'); },
      function () { $(this).removeClass('hover'); })
    .click(function () {
      $('#switcher button').toggleClass('hidden');
    });

    $('#switcher-default').addClass('selected');

  // Automatic handler names available for (jQuery 1.9.0):
  // blur focus focusin focusout load resize scroll unload click dblclick.
  // mousedown mouseup mousemove mouseover mouseout mouseenter mouseleave
  // change select submit keydown keypress keyup error contextmenu.
  $('#switcher button').click(function () {
    var bodyClass = this.id.split('-')[1];

    $('body').removeClass().addClass(bodyClass);

    $('#switcher button').removeClass('selected');
    $(this).addClass('selected');
  });

});