Employee - Employee should have either middle name or last name
             - First name, Middle name, last name should not be same
             - Should have address id and it should present in address table
             ......
             ......

     Address - In address line if there is an opening bracket it should have a matching closing bracket
             - If user give map url and it doesnt contains "http://" should show error message
            .......
            .......

public class ValidationController : Controller
{

  public JsonResult IsAddressValid(string Address)
  {

     //if Address is valid
     return Json(true, JsonRequestBehavior.AllowGet);

    //else

   return Json("Address Not valid", JsonRequestBehavior.AllowGet);

  }
}

public class SignupModel
{
    [Required]
    [Remote("IsAddressValid", "Validation")]
    public string Address{ get; set; }
}