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Editorial Team
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Asked: 2026-06-06T18:27:43+00:00

I’m making a GET request against a WCF web service. My WCF service is

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I’m making a GET request against a WCF web service. My WCF service is located at http://localhost/RestService/RestService.svc/web/GetMessage and has the following interface:

[OperationContract]
[WebGet(UriTemplate = "GetMessage", ResponseFormat = WebMessageFormat.Json)]
String GetMessage();

The endpoint is configured properly as I can make a bare call within my browser:

  <system.serviceModel>
    <behaviors>
      <serviceBehaviors>
        <behavior name="WebServiceBehavior">
          <serviceMetadata httpGetEnabled="true" />
          <serviceDebug includeExceptionDetailInFaults="true"/>
        </behavior>
      </serviceBehaviors>

      <endpointBehaviors>
        <behavior name="WebEndpointBehavior">
          <webHttp />
          </behavior>
      </endpointBehaviors>
    </behaviors>

    <services>
      <service name="TestRestService.RestService"
               behaviorConfiguration="WebServiceBehavior">
        <endpoint name="RestWeb"
                  address="web"
                  binding="webHttpBinding"
                  behaviorConfiguration="WebEndpointBehavior"
                  contract="TestRestService.IRestService" />
      </service>
    </services>
  </system.serviceModel>

Calling it via navigation in my browser returns:

{"GetMessageResult":"Hello World!"}

So far so good. No problems here. A quick look at the jQuery documentation for performing a GET yields:

<html>
    <head>
        <script type="text/javascript" src="jquery-1.7.2.min.js"></script>
        <script type="text/javascript">
            $.ajax({
                url: 'http://localhost/RestService/RestService.svc/web/GetMessage',
                type: 'GET',
                dataType: 'json',
                success: function (data) {
                    alert(data);
                },
                error: function (xhr, status, message) {
                    alert("Error: " + status + " " + message); }
                });
        </script>
    </head>
    <body>
    </body>
</html>

I run this in a small html test page using jQuery 1.72 and I get the following error:

Error: error

What gives? The error message handler that I found here gives me absolutely zero useful information. Simply put:

  • Why is my GET failing?
  • Why is the error message useless?

Solution

As it turns out, jQuery does not natively support cross-domain ajax requests as Kevin B suggested in his answer. To fix this I had to switch to using dataType: 'jsonp' and add a webHttpBinding with the crossDomainScriptEnabled property enabled:

<bindings>
  <webHttpBinding>
    <binding name="WebBindingWithScripts"
             crossDomainScriptAccessEnabled="true">
      <security mode="None" />
    </binding>
  </webHttpBinding>
</bindings>


<endpoint name="RestWeb"
          address="web"
          binding="webHttpBinding"
          behaviorConfiguration="WebEndpointBEhavior"
          bindingConfiguration="WebBindingWithScripts"
          contract="TestService.IRestService">
</endpoint>

When using only dataType: 'jsonp', you will still get errors unless you configure your WCF service to allow cross domain scripts.

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1 Answer

  1. Editorial Team

    Are you making a cross-domain request? I see you are using localhost, but that doesn’t necessarily mean you are requesting from localhost (for all we know you could be using a different port or protocol).

    There are two reasons that the request would be failing in this case:

    1. the JSON being returned has additional characters that makes it invalid json
    2. the request is coming from a different domain than the webservice.

    I expect it to be #1 due to you not seeing the same-origin error in the console. However, since you’re getting error and not parseerror, that is unlikely.

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