The XMLHTTP of Ajax

<script type= "Text/javascript" language= "JavaScript" >
<!--
Fetching data in XML
function Xmlpost (theemail)
{
var webfileurl = ". /user/checkuser.aspx? Logonname= "+ theemail;
var result = "";

if (window. ActiveXObject) {
XmlHttp = new ActiveXObject ("Microsoft.XMLHTTP");
}
else if (window. XMLHttpRequest) {
XmlHttp = new XMLHttpRequest ();
}

var xmlHttp = new ActiveXObject ("MSXML2. XMLHTTP ");
Xmlhttp.open ("POST", Webfileurl, false);
Xmlhttp.setrequestheader ("Content-type", "application/x-www-form-urlencoded");
Xmlhttp.send ("");

Xmlhttp.onreadystatechange=function ()
{
if (xmlhttp.readystate==4)
{
result = Xmlhttp.responsetext;
}
}
if (xmlhttp.status!=200)
{
Alert (' Network failure (xmlhttp.status= ' +xmlhttp.status+ '), please try again later! ');
}

result = Xmlhttp.responsetext;
result = Result.substring (0,result.indexof) ("? EX "));

If (Result!= "false")
{
return true;
}
Else
{
return false;
}
}
-->
</script> "' <summary>
"" Detects if the user exists < filename:. /user/checkuser.aspx>
"' </summary>
"' <remarks>created by Dzh @2006/06/27 18:22</remarks>
Partial Class Web_user_checkuser
Inherits System.Web.UI.Page

Protected Sub Page_Load (ByVal sender as Object, ByVal e as System.EventArgs) Handles Me.load
If request.querystring ("LogonName") is nothing Then
Response.Write ("False +"?) EX ")
Response.End ()
Exit Sub
End If

If (New EasyClick.EasyBusiness.UserBusiness). Getuserbylogonname (Request.QueryString ("LogonName"). ToString) is nothing Then
Response.Write ("False +"?) EX ")
Response.End ()
Exit Sub
Else
Response.Write ("True +"?) EX ")
Response.End ()
Exit Sub
End If
End Sub
End Class