Asp.Net / VB.Net webservice function call strange behaviour

Question

I'm using Visual Studio 2012 to create a webapp.

I'm trying to create a webservice and call a function from javascript.

this is my webservice:

Imports System.Web.Services
Imports System.Web.Services.Protocols
Imports System.ComponentModel

<System.Web.Script.Services.ScriptService()> _
<System.Web.Services.WebService(Namespace:="http://tempuri.org/")> _
<System.Web.Services.WebServiceBinding(ConformsTo:=WsiProfiles.BasicProfile1_1)> _
<ToolboxItem(False)> _
Public Class WebService1
    Inherits System.Web.Services.WebService

    <WebMethod()> _
    public Function HelloWorld(ToSomeone As string ) As String
        return "Hello World" + ToSomeone
    End Function

End Class

and this is the call to the web service

<button class="customButton" onclick="return CallService()">ProvaWebService</button>
<div id="outputDiv" style="border: 1px solid black; height: 50px;"></div>
<script type="text/javascript">

function CallService() {
    Methodo_app.WebService1.HelloWorld("Yourself", onSuccess);
}

function onSuccess(result) {
    alert(result)
    var outDiv = document.getElementById("outputDiv");
    outDiv.textContent = result;
}
</script>

I think its all configured in the right way, because I don't get error from the chrome/firefox console and if I debug the script I can see the results. But after the end of the script the result disappears from the page.

Actually I've this situation:

DEBUGGING:

I see the alert and the text in the div, but they disappear after the end of the script

NOT DEBUGGING:

I can't see the result (why the alert don't stop the script??)

If change the script with this (i add just an alert)

<script type="text/javascript">

function CallService() {
    Methodo_app.WebService1.HelloWorld("Yourself", onSuccess);
    alert("hello")
}

function onSuccess(result) {
    alert(result)
    var outDiv = document.getElementById("outputDiv");
    outDiv.textContent = result;
}

</script>

I can see the alert(result) and the text in the div but they still disappear after the end of the script.

I don't know if it's a problem of refresh or it's a sync problem

EDIT:

I've added an onFail function and I see if I run the call to webservice will fail, but if I debug the call its on success

Answer 1

Well missng

return false;

to the function

function CallService() {
    Methodo_app.WebService1.HelloWorld("Yourself", onSuccess);                    
}