I'm getting "msxml3.dll: Unspecified Error" for the line:
if (xmlHttp.readyState == 4 || xmlHttp.status == 200)
..via my Script Debugger.

<%@ Page Language="vb" AutoEventWireup="false" Codebehind="WebForm1.aspx.vb" Inherits="AjaxTesting.WebForm1"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
<HEAD>
<title>WebForm1</title>
<meta name="GENERATOR" content="Microsoft Visual Studio .NET 7.1">
<meta name="CODE_LANGUAGE" content="Visual Basic .NET 7.1">
<meta name="vs_defaultClientScript" content="JavaScript">
<meta name="vs_targetSchema" content="http://schemas.microsoft.com/intellisense/ie5">
<!-- Start script -->
<script language="javascript">
var xmlHttp = createXmlHttpRequestObject();
function createXmlHttpRequestObject()
{
var xmlHttp;
if(window.ActiveXObject)
{
try
{
xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
}
catch (e)
{
xmlHttp = false;
}
}
else
{
try
{
xmlHttp = new XMLHttpRequest();
}
catch (e)
{
xmlHttp = false;
}
}
if (!xmlHttp)
alert("Error creating the XMLHttpRequest object.");
else
return xmlHttp;
}
function process()
{
varWBS = encodeURIComponent(document.getElementById("TextBox1").value);
xmlHttp.open("GET", "test.aspx?WBS=" + varWBS);
xmlHttp.onreadystatechange = handleServerResponse;
xmlHttp.send(null);
}
function handleServerResponse()
{
if (xmlHttp.readyState == 4 || xmlHttp.status == 200)
{
document.getElementById("show").innerHTML = xmlHttp.responseText;
}
}
</script>
<!-- End script -->
</HEAD>
<body MS_POSITIONING="GridLayout">
<form id="Form1" method="post" runat="server">
<asp:TextBox id="TextBox1" style="Z-INDEX: 101; LEFT: 24px; POSITION: absolute; TOP: 24px"
runat="server" onblur='process()'></asp:TextBox>
<div id="show" />
</form>
</body>
</HTML>

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The code behind for the text.aspx page is very simple for now, and is:


Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
'Put user code to initialize the page here
If Server.HtmlEncode(Request.QueryString("WBS")).ToString = "1.2.8.5.001" Then
Response.Write("Please enter another WBS!")
Else
Response.Write("You can use this one!")
End If
End Sub