jQuery ajax not working in Sharepoint Visual Web Part

Question

So I'm trying to do the basic example of jQuery ajax in my Sharepoint 2013 Visual WebPart:

<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js" type="text/javascript"></script>
<script type = "text/javascript">
function ShowCurrentTime() {
    $.ajax({
        type: "POST",
        url: "SPtest.aspx/GetCurrentTime",
        data: '{name: "' + $("#<%=txtUserName.ClientID%>")[0].value + '" }',
        contentType: "application/json; charset=utf-8",
        dataType: "json",
        success: OnSuccess,
        failure: function(response) {
            alert(response.d);
        }
    });
}
function OnSuccess(response) {
    alert(response.d);
}
</script>

<div>
Your Name :
<asp:TextBox ID="txtUserName" runat="server"></asp:TextBox>
<input id="btnGetTime" type="button" value="Show Current Time"
    onclick = "ShowCurrentTime()" />
</div>

And on server in VisualWebPart1UserControl.ascx.cs

[System.Web.Services.WebMethod]
public static string GetCurrentTime(string name)
{
    return "Hello " + name + Environment.NewLine + "The Current Time is: "
        + DateTime.Now.ToString();
}

And it's not working, if open debugger in chrome I can see that it's throwing this error 500 on server side:

Server Error in '/' Application.
Unknown web method GetCurrentTime.
Parameter name: methodName
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 

Exception Details: System.ArgumentException: Unknown web method GetCurrentTime.
Parameter name: methodName

Source Error: 

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace: 


[ArgumentException: Unknown web method GetCurrentTime.
Parameter name: methodName]
   System.Web.Script.Services.WebServiceData.GetMethodData(String methodName) +806855
   System.Web.Handlers.ScriptModule.OnPostAcquireRequestState(Object sender, EventArgs eventArgs) +238
   System.Web.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +136
   System.Web.HttpApplication.ExecuteStepImpl(IExecutionStep step) +195
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +88

Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.7.2623.0

I have no idea what is wrong.

Answer 1

The question had been answered here.

You cant add a WebMethod to a webpart. A webpart is a server control and outputs html to the page.