Listing 3.7: completely remove discrete handlers.

Chapter 3/03.js

@@ -1,19 +1,13 @@
 $(document).ready(function () {
   'use strict';
-
+  $('#switcher-default').addClass('selected');
+  
   $('#switcher button').on('click', function () {
-    $('body').removeClass();
+    var bodyClass = this.id.split('-')[1];
+
+    $('body').removeClass().addClass(bodyClass);
+
     $('#switcher button').removeClass('selected');
     $(this).addClass('selected');
   });
-
-  $('#switcher-default').addClass('selected');
-
-  $('#switcher-narrow').on('click', function () {
-      $('body').addClass('narrow');
-    });
-  $('#switcher-large').on('click', function () {
-      $('body').addClass('large');
-    });
-
 });