How to make a button that triggers javascript action ? v6

Hi, I'm new in OpenERP web module development and I'm currently trying to make a simple module that just display a button, and if I clic the button I want javascript to write a message in the developper console of my browser. I am following a tutorial : doc.openerp.com/trunk/developers/web/module/ But it doesn't work, and I'm not understanding what I made wrong. I have the following files : web_example ├── __init__.py ├── __openerp__.py ├── web_example.xml ├── static ├── src └── js └── first_module.js __init__.py is empty __openerp__.py { 'name': "Web Example", 'description': "Basic example of a (future) web module", 'category': 'Hidden', 'depends': ['web'], 'data': ['web_example.xml'], 'js': ['static/src/js/first_module.js'], } web_example.xml Example Client Actionexample.action first_module.js openerp.web_example = function (instance) { instance.web.client_actions.add('example.action', 'instance.web_example.action'); instance.web_example.action = function (parent, action) { console.log("Executed the action", action); }; }; According to the tutorial, this code should make a button in the menu, and if you click the button you get a message in the console. My problem is that when I try to upgrade my module i get errors : AssertionError: No window action defined for this id action_client_example ! Verify that this is a window action or add a type argument. And here is the complete log : OpenERP Server Error Client Traceback (most recent call last): File "/opt/openerp/server/openerp/addons/web/common/http.py", line 180, in dispatch response["result"] = method(controller, self, **self.params) File "/opt/openerp/server/openerp/addons/web/controllers/main.py", line 1004, in call_button action = self.call_common(req, model, method, args, domain_id, context_id) File "/opt/openerp/server/openerp/addons/web/controllers/main.py", line 948, in call_common return self._call_kw(req, model, method, args, {}) File "/opt/openerp/server/openerp/addons/web/controllers/main.py", line 962, in _call_kw return getattr(req.session.model(model), method)(*args, **kwargs) File "/opt/openerp/server/openerp/addons/web/common/openerplib/main.py", line 250, in proxy args, kw) File "/opt/openerp/server/openerp/addons/web/common/openerplib/main.py", line 117, in proxy result = self.connector.send(self.service_name, method, *args) File "/opt/openerp/server/openerp/addons/web/common/http.py", line 611, in send raise fault Server Traceback (most recent call last): File "/opt/openerp/server/openerp/addons/web/common/http.py", line 592, in send result = openerp.netsvc.dispatch_rpc(service_name, method, args) File "/opt/openerp/server/openerp/netsvc.py", line 360, in dispatch_rpc result = ExportService.getService(service_name).dispatch(method, params) File "/opt/openerp/server/openerp/service/web_services.py", line 569, in dispatch security.check(db,uid,passwd) File "/opt/openerp/server/openerp/service/security.py", line 40, in check pool = pooler.get_pool(db) File "/opt/openerp/server/openerp/pooler.py", line 50, in get_pool return get_db_and_pool(db_name, force_demo, status, update_module)[1] File "/opt/openerp/server/openerp/pooler.py", line 33, in get_db_and_pool registry = RegistryManager.get(db_name, force_demo, status, update_module, pooljobs) File "/opt/openerp/server/openerp/modules/registry.py", line 138, in get update_module, pooljobs) File "/opt/openerp/server/openerp/modules/registry.py", line 160, in new openerp.modules.load_modules(registry.db, force_demo, status, update_module) File "/opt/openerp/server/openerp/modules/loading.py", line 334, in load_modules processed = load_marked_modules(cr, graph, states_to_load, force, status, report, loaded_modules) File "/opt/openerp/server/openerp/modules/loading.py", line 253, in load_marked_modules loaded, processed = load_module_graph(cr, graph, progressdict, report=report, skip_modules=loaded_modules) File "/opt/openerp/server/openerp/modules/loading.py", line 193, in load_module_graph load_data(module_name, idref, mode) File "/opt/openerp/server/openerp/modules/loading.py", line 92, in load_data = lambda *args: _load_data(cr, *args, kind='data') File "/opt/openerp/server/openerp/modules/loading.py", line 138, in _load_data tools.convert_xml_import(cr, module_name, fp, idref, mode, noupdate, report) File "/opt/openerp/server/openerp/tools/convert.py", line 997, in convert_xml_import obj.parse(doc.getroot()) File "/opt/openerp/server/openerp/tools/convert.py", line 890, in parse self._tags[rec.tag](self.cr, rec, n) File "/opt/openerp/server/openerp/tools/convert.py", line 632, in _tag_menuitem "Verify that this is a window action or add a type argument." % (a_action,) AssertionError: No window action defined for this id action_client_example ! Verify that this is a window action or add a type argument. So my question is What am I doing wrong ? Is there another way to just get a button that trigger javascript action ? Thanks.