Call a AJAX Enabled Asp.Net Web Service from JavaScript

Hi,



I want to call a webservice from javascript ..
suppose I have a Master page 'A' which has a script manager and i have a content page 'B' in which i need to consume the webservice


How will i call the webservice??
<asp:ScriptManager ID="ScriptManager1" Runat="server">
                <Services>
                <asp:ServiceReference Path="xxx.asmx" />
                </Services>
                </asp:ScriptManager>


but I dont want to reference the webservice in master page ...
My Script Method is in master page ...