Microsoft JScript runtime error: 'Sys' is undefined

Question

I have a page with the following code on it:

<script type="text/javascript" language="javascript">
    /// <reference name="MicrosoftAjax.js" />

    Sys.WebForms.PageRequestManager.getInstance().add_endRequest(EndRequestHandler);

    function EndRequestHandler(sender, args)
    {
        ToggleTimeDiv();
    }
</script>

When the page loads I get the following error:

• Microsoft JScript runtime error: 'Sys' is undefined

I'm using Visual Studio 2008 Standard Edition. What is causing this error?

Answer 1

Hai Achilies,

Is your <script> block ahead of your ScriptManager?

http://encosia.com/2007/08/16/updated-your-webconfig-but-sys-is-still-undefined/