If you are adding Page Method on your ASP .Net page and you see this compile error:

the type or namespace name ‘webmethod’ could not be found….

then you are missing one of these things:

A. Make sure you have reference to System.Web.Services on your class.

using System.Web.Services;

B. Make sure on your web.config you have

<system.web>
<httpModules>
<add name=”ScriptModule” type=”System.Web.Handlers.ScriptModule, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35″/>
</httpModules>
</system.web>

C. Make sure you have EnablePageMethods set to true on your ScriptManager

<asp:ScriptManager ID=”ScriptManager1″ EnablePageMethods=”true” runat=”server”>
</asp:ScriptManager>