Control the CDN paths for ASP.NET 4.x scripts via the ScriptManager

Global.asax.cs

using System;
using System.Reflection;
using System.Web;
using System.Web.UI;

namespace WebApplication34
{
    public class Global : HttpApplication
    {
        void Application_Start(object sender, EventArgs e)
        {
            AddScriptMapping("WebForms.js", typeof(Page).Assembly, "window.WebForm_SetElementY");
            AddScriptMapping("WebUIValidation.js", typeof(Page).Assembly, "window.ValidationSummaryOnSubmit");
            AddScriptMapping("MenuStandards.js", typeof(Page).Assembly, "window.Sys && window.Sys.WebForms && window.Sys.WebForms.Menu");
            AddScriptMapping("Menu.js", typeof(Page).Assembly, "window.Menu_ClearInterval");
            AddScriptMapping("Focus.js", typeof(Page).Assembly, "window.WebForm_FindFirstFocusableChild");
            AddScriptMapping("GridView.js", typeof(Page).Assembly, "window.GridView");
            AddScriptMapping("DetailsView.js", typeof(Page).Assembly, "window.DetailsView");
            AddScriptMapping("TreeView.js", typeof(Page).Assembly, "window.TreeView_UnhoverNode");
            AddScriptMapping("WebParts.js", typeof(Page).Assembly, "window.WebPartManager_SubmitPage");
            AddScriptMapping("SmartNav.js", typeof(Page).Assembly, "window.__smartNav");
            AddScriptMapping("MicrosoftAjax.js", typeof(ScriptManager).Assembly, "window.Sys && Sys._Application && Sys.Observer");
            AddScriptMapping("MicrosoftAjaxCore.js", typeof(ScriptManager).Assembly, "window.Type && Sys.Observer");
            AddScriptMapping("MicrosoftAjaxGlobalization.js", typeof(ScriptManager).Assembly, "window.Sys && Sys.CultureInfo");
            AddScriptMapping("MicrosoftAjaxSerialization.js", typeof(ScriptManager).Assembly, "window.Sys && Sys.Serialization");
            AddScriptMapping("MicrosoftAjaxComponentModel.js", typeof(ScriptManager).Assembly, "window.Sys && Sys.CommandEventArgs");
            AddScriptMapping("MicrosoftAjaxNetwork.js", typeof(ScriptManager).Assembly, "window.Sys && Sys.Net && Sys.Net.WebRequestExecutor");
            AddScriptMapping("MicrosoftAjaxHistory.js", typeof(ScriptManager).Assembly, "window.Sys && Sys.HistoryEventArgs");
            AddScriptMapping("MicrosoftAjaxWebServices.js", typeof(ScriptManager).Assembly, "window.Sys && Sys.Net && Sys.Net.WebServiceProxy");
            AddScriptMapping("MicrosoftAjaxTimer.js", typeof(ScriptManager).Assembly, "window.Sys && Sys.UI && Sys.UI._Timer");
            AddScriptMapping("MicrosoftAjaxWebForms.js", typeof(ScriptManager).Assembly, "window.Sys && Sys.WebForms");
            AddScriptMapping("MicrosoftAjaxApplicationServices.js", typeof(ScriptManager).Assembly, "window.Sys && Sys.Services");
        }

        private static readonly string CDN_PATH_PREFIX = "http://ajax.aspnetcdn.com/ajax/4.5.1/1/";

        private static void AddScriptMapping(string name, Assembly assembly, string loadSuccessExpression)
        {
            ScriptManager.ScriptResourceMapping.AddDefinition(name, new ScriptResourceDefinition
            {
                ResourceName = name,
                ResourceAssembly = assembly,
                CdnPath = CDN_PATH_PREFIX + name,
                LoadSuccessExpression = loadSuccessExpression,
                CdnSupportsSecureConnection = true
            });
        }
    }
}