learning_jquery/Chapter 3/listings/3.13.js

$(document).ready(function() {
  $('#switcher h3').hover(function() {
    $(this).addClass('hover');
  }, function() {
    $(this).removeClass('hover');
  });
});

$(document).ready(function() {
  $('#switcher').click(function(event) {
    $('#switcher button').toggleClass('hidden');
  });
});

$(document).ready(function() {
  $('#switcher-default').addClass('selected');

  $('#switcher button').click(function(event) {
    var bodyClass = this.id.split('-')[1];

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

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