Calling a javascript in my razor page from a controller in MVC4

See more:

Javascript

MVC4

ASP.NET5

In my controller I have this function:

Function AppError() As ActionResult
          Dim myScript As Object = "popup(" + Properties.postError + ")"
          Return RedirectToAction("main", myScript)
      End Function

With this function I want to call my razor page where I have a Javascript named `popup` whith a parameter `Properties.postError`.

My script is:

<script type="text/javascript">
       var errMsg;
       function popup(msg) {
           errMsg = msg;
           window.alert(errMsg);
           window.window.focus();
           if (window.confirm)
               errmsg = '';
           msg = '';
       }
   </script>

What I need is to popup the error message.
I follow the programm throu my debugger and I saw that it goes to my page.
But no error message window raise up.
I have already search in the web for this option without any success.
Is someone to assist me on this issue?

What I have tried:

ADDITION - 16/2/19 12:50
what I have done so far is the following:

Function CBError() As ActionResult
        Dim myScript As Object = "popup(" + Properties.postError + ")"
        ViewData.Add(New KeyValuePair(Of String, Object)("ScriptName", myScript))
        Return View("main", myScript)
    End Function

As we can see I've change the function by addiding the ViewData
I Add a value pair arguments 1) the name 2) the value
The action of addition it works just fine and the dictionery receive it.
I my script (which is in my reazor page) I put the following:

<script type="text/javascript">
   var vd = @ViewData.Item(0);
       function popup(msg) {
            var errMsg;
        errMsg = msg;
        window.alert(errMsg);
        window.window.focus();
        if (window.confirm)
            errmsg = '';
        msg = '';
        //{ window.location.href = "/" }
    }
</script>

When I stop (with the bebugger) in the instruction var vd = @ViewData.Item(0); I see that the ViewData is complitely empty. No values no nothing.
I also add this window.onload = @Html.Raw(ViewBag.MyScript);
And in debugger threw me an error

"Uncaught SyntaxError: Unexpected token ;"



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