--- web_example/static/src/js/first_module.js
+++ web_example/static/src/js/first_module.js
@@ -1,7 +1,19 @@
 // static/src/js/first_module.js
 openerp.web_example = function (instance) {
     instance.web.client_actions.add('example.action', 'instance.web_example.Action');
     instance.web_example.Action = instance.web.Widget.extend({
-        template: 'web_example.action'
+        template: 'web_example.action',
+        events: {
+            'click .oe_web_example_start button': 'watch_start',
+            'click .oe_web_example_stop button': 'watch_stop'
+        },
+        watch_start: function () {
+            this.$el.addClass('oe_web_example_started')
+                    .removeClass('oe_web_example_stopped');
+        },
+        watch_stop: function () {
+            this.$el.removeClass('oe_web_example_started')
+                    .addClass('oe_web_example_stopped');
+        },
     });
 };