Create a simple page like
Default.aspx
<%@ Page Language="VB" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>Untitled Page</title>
<script language="Javascript">
function xmlhttpPost(strURL) {
// alert(strURL)
var xmlHttpReq = false;
var self = this;
// Mozilla/Safari
if (window.XMLHttpRequest) {
self.xmlHttpReq = new XMLHttpRequest();
}
// IE
else if (window.ActiveXObject) {
self.xmlHttpReq = new ActiveXObject("Microsoft.XMLHTTP");
}
self.xmlHttpReq.open('POST', strURL, true);
self.xmlHttpReq.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
self.xmlHttpReq.onreadystatechange = function() {
if (self.xmlHttpReq.readyState == 4) {alert('hi');
updatepage(self.xmlHttpReq.responseText);
}
}
self.xmlHttpReq.send(getquerystring());
}
function getquerystring() {
//var form = document.forms['f1'];
// var word = form.word.value;
// qstr = 'w=' + escape(word); // NOTE: no '?' before querystring
// return qstr;
}
function updatepage(str){
alert(str)
document.getElementById("result").innerHTML = str;
}
</script>
</head>
<body>
<form name="f1">
<p>word: <input name="word" type="text">
<input value="Go" type="button"
onclick='JavaScript:xmlhttpPost("http://localhost:2835/website1/WebService.asmx/HelloWorld")'></p>
<div id="result"></div>
</form>
</body>
</html>
Then Create a webservice
Imports System.Web
Imports System.Web.Services
Imports System.Web.Services.Protocols
<WebService(Namespace:="http://tempuri.org/")> _
<WebServiceBinding(ConformsTo:=WsiProfiles.BasicProfile1_1)> _
<Global.Microsoft.VisualBasic.CompilerServices.DesignerGenerated()> _
Public Class WebService
Inherits System.Web.Services.WebService
<WebMethod()> _
Public Function HelloWorld() As String
Return "Hello World"
End Function
End Class
http://dotnetclassic.com/post/AjaxWithJavascript.aspx