Creating a ASMX-page to leverage some service functionality to a client is fairly easy. The nice thing about that is, that you can even consume these services from JavaScript.

But out-of-the-box you can only call those services either via SOAP 1.1, SOAP 1.2 or a POST-request. But what if you want to use a plain-ol’ GET-request? You’ll always get an error-message stating, that GET is not supported – what a bummer.

But working around this problem is quite easy to do. Just open up your code-behind of your ASMX-Service and add

[ScriptMethod(UseHttpGet = true)]

To the method you’re calling. Finally you’ll also have to add the HTTP-GET to the list of "known" protocolls for webservices in the web.config. This is done by adding

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

to the system.web section in the web.config.

Thats all.