How to find the default hierarchy name of a Dimension in JavaScript Pivot Client ?

public Dictionary<string, object> InitializeClient(string action, string customObject, string clientParams)
{
OlapDataManager DataManager = null;
DataManager = new OlapDataManager(connectionString);
DataManager.SetCurrentReport(CreateOlapReport());
string defaultHierarchyName = "";
var Dimensions = DataManager.CurrentCubeSchema.Dimensions;
for (int i = 0; i < Dimensions.Count; i++)
{
if(Dimensions[i].Name == "Enter valid dimension name")
defaultHierarchyName = Dimensions[i].DefaultHierarchyName;
}
return olapClientHelper.GetJsonData(action, DataManager, clientParams);
}

Public Function InitializeClient(ByVal action As String, ByVal customObject As String, ByVal clientParams As String) As Dictionary(Of String, Object)
Dim DataManager As OlapDataManager = Nothing
DataManager = New OlapDataManager(connectionString)
DataManager.SetCurrentReport(CreateOlapReport())
Dim defaultHierarchyName As String = ""
Dim Dimensions = DataManager.CurrentCubeSchema.Dimensions
For i As Integer = 0 To Dimensions.Count - 1
If Dimensions(i).Name = "Enter valid dimension name" Then
defaultHierarchyName = Dimensions(i).DefaultHierarchyName
End If
Next i
Return olapClientHelper.GetJsonData(action, DataManager, clientParams)
End Function