title: Two methods with different signatures, jquery is not calling correct method
body: <p>There are two methods <code>GetUserAssignedSystems()</code> and <code>GetUserAssignedSystems(string Id)</code>
  These methods act very differently from each other.  The problem is, when I want to call <code>GetUserAssignedSystems(string Id)</code>, the parameter-less method is called.</p>
  
  <p>Here are the methods:</p>
  
  <pre><code>[WebMethod]
  [ScriptMethod]
  public IEnumerable GetUserAssignedSystems(string cacId)
  {
      return Data.UserManager.GetUserAssingedSystems(cacId);
  }
  
  [WebMethod]
  [ScriptMethod]
  public IEnumerable GetUserAssignedSystems()
  {
      //do something else
  }
  </code></pre>
  
  <p>Here is the jQuery making the call:</p>
  
  <pre><code>CallMfttService("ServiceLayer/UserManager.asmx/GetUserAssignedSystems", 
          "{'cacId':'" + $('#EditUserCacId').val() + "'}", function(result) {
              for (var userSystem in result.d) {
                  $('input[UserSystemID=' + result.d[userSystem] + ']').attr(
                      'checked', 'true');
              }
          });
  </code></pre>
  
  <p>Any ideas why this method is being ignored?</p>
  
  <p><strong>UPDATE</strong></p>
  
  <p>Here is the code for the CallMfttService</p>
  
  <pre><code>function CallMfttService(method, jsonParameters, successCallback, errorCallback){
  if (errorCallback == undefined)
  {
      errorCallback = function(xhr)
      {
          if (xhr.status == 501)
          {
              alert(xhr.statusText);
          }
          else
          {
              alert("Unexpected Error");
          }
      }
  }
  
  $.ajax({
      type: "POST",
      url: method,
      data: jsonParameters,
      contentType: "application/json; charset=utf-8",
      dataType: "json",
      success: successCallback,
      error: errorCallback
  });
  </code></pre>
  
  <p>}</p>