Call VB function from javascript - asp.net

Question

I have a javascript in my asp file where I would like to call a vb function from.
Asp javascript function:
<script type="text/javascript">
function functionName(sender, args) {
var variable = args.get_value();
PageMethods.VBFunctionName(variable);
}
</script>
Function in VB:
<System.Web.Services.WebMethod()>
Public Shared Function VBFunctionName(variable As String) As String
Dim result As String = variable
Return result.ToString()
End Function
And, I have also added the ScriptManager to enable page methods:
<asp:ScriptManager ID="sm" runat="server" EnablePageMethods="True"></asp:ScriptManager>
But, It is not working! In the asp file, when I type 'PageMethods' the autocomplete for this option it's not available. So, I think the error is with the EnablePageMethods.
How could I resolve this problem?

Answer 1

The problem with your code is that you are making an Ajax call but not setting any callback to read the response from the server. You need to define a callback function (and optionally a failure function) to set what you are going to do with the response.
So your script tag should look like this:-
<script type="text/javascript">
function functionName(sender, args) {
var variable = args.get_value();
PageMethods.VBFunctionName(variable,onSuccess); //pass callback function
}
function onSuccess(response) {
alert(response); //Do whatever you wanna do with response.
}
</script>
Also, since we are working inside javascript script tag, I don't think Visual Studio will be able to suggest u the server methods.

Answer 2

I prefer using JQuery to call VB Function from javascript.
<script type="text/javascript">
function functionName(sender, args) {
var variable = args.get_value();
$.get( "#Url.Action("VBFunctionName")?variable=" + variable, function( data ) {
alert(data);
});
}
</script>