Listing 1: HTMLStartPage.htm
<html><head><script>
var objRequest;
function SendValue(val)
{
//Initialize *************************************
try
{ //MS IE Browsers
objRequest=new ActiveXObject("Msxml2.XMLHTTP");}
catch(e)
{
try
{//All Non-IE Browsers
objRequest=new ActiveXObject("Microsoft.XMLHTTP");}
catch(oc)
{objRequest=null;}
}
if(!objRequest&&typeof XMLHttpRequest!="undefined")
{ objRequest=new XMLHttpRequest();}
//*********************************************
//Web page that handles requests
var url="http://localhost/VBNETSample/HandleAjaxRequests.aspx?sStringIn=" + val;
if(objRequest!=null)
{ objRequest.onreadystatechange = Process;
objRequest.open("GET", url, true);
objRequest.send(null);
}
}
function Process()
{
if (objRequest.readyState == 4)
//A "4" value means we can now use the XMLHttpRequest returned data
{ if (objRequest.status == 200)
{ document.getElementById("txtEchoOutPut").innerText = objRequest.responseText;
//IE
//document.getElementById("txtEchoOutPut").innerHTML = objRequest.responseText;
//Other browsers
}
else
{ document.getElementById("txtEchoOutPut").innerHTML= "There was a problem retrieving
data:<br>" + objRequest.statusText;}
}
}
</script>
</head>
<body>
<form name="frm1" ID="frm1">
Type in this text box:<input name="txtStart" onKeyUp="SendValue(this.value)"
style="WIDTH:500px"><br>
Output will appear here:<input name="txtEchoOutPut" id="txtEchoOutPut"
style="WIDTH:500px" >
</form></body></html>
Listing 2: HandleAjaxRequests.aspx
Public Class HandleAjaxRequests
Inherits System.Web.UI.Page
Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs)
Handles MyBase.Load
Dim sStringOut As String 'Create a string variable to echo back to the browser
sStringOut = "You typed: " + Request.QueryString("sStringIn").ToString()
Response.Write(sStringOut) //Echo back the text that we received
End Sub
End Class