Issues in invoking WebServices using Javascript in ASP.NET

I can't seem to figure out why I am unable to call a webservice. What could I be missing? @@

I'm attempting to follow the instructions provided here: How to call an ASP.Net Web Service in javascript

Below are my codes, but they are failing to work.

This is the webservice code snippet:

using System;
using System.Collections.Generic;
using System.Web;
using System.Web.Services;
using System.Web.Services.Protocols;
using System.Web.Script.Services;

namespace Library
{
    [WebService(Namespace = "http://tempuri.org/")]
    [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
    [System.ComponentModel.ToolboxItem(false)]
    [System.Web.Script.Services.ScriptService()]
    public class ReleaseSessionObject : System.Web.Services.WebService
    {
        [WebMethod]
        public string HelloWord()
        {
            return "Hellow Word!";
        }
    }
}

And this is my ASP.NET page code snippet:

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm6.aspx.cs" Inherits="Library.WebForm6" %>

<!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 runat="server">
    <title></title>

</head>
<body>
    <form id="form1" runat="server">
    <div>

    <script src="ReleaseSessionObject.asmx" type="text/javascript"></script>
    <script type="text/javascript">
        function HelloWorld() {
            try {
                var a = Library.ReleaseSessionObject.HelloWorld();
                alert(a);
            }
            catch (err) {
                alert(err.Message); 
            }
        };
    </script>

    <asp:ScriptManager ID="ScriptManager1" runat="server">
      <Services>
        <asp:ServiceReference Path="~/ReleaseSessionObject.asmx" />
      </Services>
    </asp:ScriptManager>

    <input type="button" onclick="HelloWorld();" value="Click This" />

    </div>
    </form>
</body>
</html>

Both the ASP.NET page and Service files are located in the same folder.

However, when clicking on the button, it returns: undefined

Answer №1

Did you remember to include a web reference in your project? By doing this, the proxy will be generated and you can begin utilizing the methods of the web service. Make sure to take a look at this helpful tutorial.

Don't forget to explore the resources available on MSDN as well.

Answer №2

Consider implementing asynchronous functionality:

function Greetings() {
    Library.GreetUser(OnFinished);
}

function OnFinished(response) {
    alert(response);
}

Answer №3

The function defined in the web service asmx file is written as HelloWord, but in the HTML markup it's spelled as HelloWorld. The error message "undefined" pops up because the method couldn't be found, likely due to a spelling mistake.

If you're having trouble, consider looking into this helpful example: Directly calling ASMX web services from JavaScript

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