Recently I was getting error when I am calling web service using Java script. I searching on net and debugging I have found following things.

Any web service support three kinds of protocol HttpGet,HttpPost and SOAP. In framework 1.0 it was enabled by default but after 1.0 framework it will not be enabled by default due to security issues and WS-Specifications. So we have to enabled them via putting configuration settings in web.config. Here is the code for that.

<configuration>

   <system.web>

    <webservices>

       <protocols>

           <add name="HttpGet"></add>

           <add name="HttpPost"></add>

       </protocols>

   </webservices>

   </system.web>

</configuration>

Hope this will help you. Stay tuned for more. Till that Happy programming!!!.