Call asmx web service from jQuery Ajax

I had earlier posted a tutorial on how to call c# server side methods using JavaScript. It made use of Page Method provided by .NET framework.
In this tutorial, we'll see how to call an asmx service web method using jQuery Ajax. So lets start by creating a web application in Visual Studio. Download and include the latest jQuery in your html or aspx page.
<script src=" jquery-2.1.1.js="" scripts="" type="text/javascript"></script>