When you upgrade your site to use the ASP.NET AJAX Beta 2, you must add a new HttpHandler in the web.config file. Under the <httpHandler> element in the web.config, add the following handler:<add verb="GET" path="ScriptResource.axd" type="Microsoft.Web.Handler... validate="false"/> Otherwise you may receive 'Sys' is undefined error message...

I have upgraded an Ajax-enabled ASP.NET site that I'm working on to use the latest ASP.NET AJAX Extenstion Beta 2. My site use external javascript files that is being registered with the ScriptManager, like:<asp:ScriptManager runat="server" ID="ScriptManager1"> <Scripts> <asp:ScriptReference Path="~/scripts/script_file... /> <asp:ScriptReference Path="~/scripts/script_file... /> </Scripts> </asp:ScriptManager> .csharpcode, .csharpcode pre { font-size: small;...