WCF JSON Format - while consuming in Client side getting an

Client side Code

1. I have created web application and added service reference to the Client Project

2. I tried creating a client Object like this -

Service1Client a = new Service1Client();

but getting an error message :- Could not find default endpoint element that references contract 'ServiceReference_test.IService1' in the ServiceModel client configuration section. This might be because no configuration file was found for your application, or because no endpoint element matching this contract could be found in the client element.

Could you please let me know what mistake am doing, I am new to WCF please help me