Call Web Methods Of WebService In Javascript

I'm doing a project in asp.net with a web services. My web services and my asp.net project is separate and my asp.net projet have a reference of my web services. i'm using visual studio 2008 framework 3.5 and my service web is in vb.net. i want to call the web methods of my web services in javascript my script manager is declared

<asp:ScriptManager runat="server" ID="scriptManager" EnablePageMethods="true" >
<Services>
<asp:ServiceReference path="http://localhost:2931/ServiceCompas.asmx"/>
</Services>
</asp:ScriptManager>
the javascript fuctions
<script type="text/javascript">
function test() {
alert('test');
Service1.Liste_Carte(Onsucced);
}
function Onsucced(resultat) {
alert('je suis passée');
}
</script>

service1 is the class of my Webservice and i call the function test with my button <input name="btnRecherche" class="btnRechercher" type="button" value="Rechercher un emplacement" onclick="test()" /> the problem is : JavaScript say Service1 is not defined but why .... What's the problem ? I've checked many forums and videos every body did it
sorry for the french variable