How to Make Multiple Parallel WCF Service Calls from jquery - wcf

Question

I have to make multiple WCF service calls by using jquery to update different areas of the web page after a specified time interval. If I make a single call to the WCF service it works fine, but when there are two or more parallel calls to the WCF service no response is received.
All the service calls are made after some specified time-interval. Following is the code of one of them:
var type = "POST";
var contentType = "application/json; charset=utf-8";
var dataType = "json";
var processData = true;
function LoadData()
{
var url = serviceURL;
var data = '{}';
CallService(url, data, LoadDataSuccess);
}
function LoadDataSuccess(result)
{
if (dataType == "json")
{
//other code...
setTimeout("LoadData()", 5000);
}
}
function CallService(url, data, SuccessMethod)
{
$.ajax({
type: type, //GET or POST or PUT or DELETE verb
url: url, // Location of the service
data: data, //Data sent to server
contentType: contentType, // content type sent to server
dataType: dataType, //Expected data format from server
processdata: processData, //True or False
success: function (msg)
{
SuccessMethod(msg);
},
error: ServiceFailed
});
}
function ServiceFailed(result)
{
alert('Service call failed: ' + result.status + '' + result.statusText);
type = null; contentType = null; dataType = null; processData = null;
}
And my wcf service looks like this:
public interface ITestService
{
[OperationContract]
[WebInvoke(Method = "POST",
BodyStyle = WebMessageBodyStyle.Wrapped,
ResponseFormat = WebMessageFormat.Json,
RequestFormat = WebMessageFormat.Json)]
List<Data> GetData();
[OperationContract]
[WebInvoke(Method = "POST",
BodyStyle = WebMessageBodyStyle.Wrapped,
ResponseFormat = WebMessageFormat.Json,
RequestFormat = WebMessageFormat.Json)]
List<Data> GetUser();
[OperationContract]
[WebInvoke(Method = "POST",
BodyStyle = WebMessageBodyStyle.Wrapped,
ResponseFormat = WebMessageFormat.Json,
RequestFormat = WebMessageFormat.Json)]
List<Data> GetCustomer();
}
And the configuration looks like this:
<system.serviceModel>
<serviceHostingEnvironment multipleSiteBindingsEnabled="true" />
<behaviors>
<endpointBehaviors>
<behavior name="EndpBehavior">
<webHttp />
</behavior>
</endpointBehaviors>
<serviceBehaviors>
<behavior name="ServiceBehavior">
<serviceMetadata httpGetEnabled="true" />
<serviceDebug includeExceptionDetailInFaults="true" />
</behavior>
<behavior name="">
<serviceMetadata httpGetEnabled="true" />
<serviceDebug includeExceptionDetailInFaults="false" />
</behavior>
</serviceBehaviors>
</behaviors>
<services>
<service behaviorConfiguration="ServiceBehavior" name="TestService">
<endpoint address="" binding="webHttpBinding" contract="ITestService" behaviorConfiguration="EndpBehavior"/>
</service>
</services>
</system.serviceModel>