Client Side Issue: asp.net ajax client-side framework failed to load

When accessing a web page, I am receiving the following errors:

"asp.net ajax client-side framework failed to load"
"'sys is undefined"

Environment:
Internet Explorer ver. 7.0
.Net versions:
2.0
3.0
3.5
KyleWetzelEUCAsked:
Who is Participating?
 
Kumaraswamy RCommented:
After including a control from the ASP.Net AjaxControlToolkit version 3.5 -  we got this error:
Microsoft JScript runtime error: AjaxControlToolkit requires ASP.NET Ajax 4.0 scripts. Ensure the correct version of the scripts are referenced. If you are using an ASP.NET ScriptManager, switch to the ToolkitScriptManager in AjaxControlToolkit.dll.
3.1.1.      Solution
I believe there are many other problems which can cause this symptom, but in my case, as the error message says, the solution is that you need to include the “ToolkitScriptManager” rather than the standard “ScriptManager”
To add the ToolkitScriptManager, you first need to include the assembly namespace on your aspx page.
<%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit"
TagPrefix=" AjaxToolkit" %>
Or in the “web.config”
<system.web>
            <httpRuntime maxRequestLength="10240"/>
            <pages>
                  <tagMapping>
                        
                  </tagMapping>
                  <controls>
                        <add tagPrefix="asp" namespace="System.Web.UI" assembly="System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
                        <add tagPrefix="asp" namespace="System.Web.UI.WebControls" assembly="System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
                     <add tagPrefix="ajaxToolkit" assembly="AjaxControlToolkit" namespace="AjaxControlToolkit"  />
                        <add tagPrefix="cc1" assembly="AjaxControlToolkit" namespace="AjaxControlToolkit.HTMLEditor"  />
                 </controls>
            </pages>
If you control is right on your main page, chances are you have already done this.  But in my case the Ajax control was embedded in a user control, so I didn’t have it on the main page yet.
Then you can simply include the manager by changing the standard script manager
<asp:ScriptManager ID="scriptMaster" runat="server"></asp:ScriptManager>
To this:
<asp:ToolkitScriptManager ID="toolkitScriptMaster" runat="server">
</asp:ToolkitScriptManager>

3.2.      Microsoft JScript runtime error
We got this annoying error recently in a website I've been working on.  It worked perfectly fine locally, it worked fine after uploading to the web server on my machine and other machines in the lab (various browsers).  Then, it turns out, it doesn't work on (one of) the client's machines.  Of course, I'm unable to replicate the error locally.
I looked around and it seems the first solution was to clear the cache.  A lot of people said that Ctrl+F5 works, others said they needed to manually clear the cache and then restart the browser.  Well, neither of those worked.
3.2.1.      Solution
Fortunatelly, the solution turned out to be pretty easy:  Set the "CombineScripts" property of the ToolkitScriptManager to false.
<ajaxToolkit:ToolkitScriptManager runat="server" ID="ajaxScriptManager" EnablePartialRendering="true" CombineScripts="false" />
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Carl TawnSystems and Integration DeveloperCommented:
It usually means that you are missing the Ajax Extensions from your project, but there could be other reasons.

Check this thread for a few options to try:

    http://forums.asp.net/t/1207960.aspx
0
 
Alpesh PatelAssistant ConsultantCommented:
There is some missing dependencies. Pls include all of them. May it will solve your problem.
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