# Using Custom Attributes Declaratively

Custom attributes can be added to a node by simply adding an HTML attribute to a **RadTreeNode** tag. Then access the attribute in [server-side](https://www.telerik.com/products/aspnet-ajax/documentation/controls/treeview/custom-attributes/using-custom-attributes-at-the-server) or [client-side](https://www.telerik.com/products/aspnet-ajax/documentation/controls/treeview/custom-attributes/using-custom-attributes-at-the-client) code. The example below defines a custom "ScientificName" attribute. The attribute is accessed in the server-side **NodeClick** event through the **Attributes** property.

> caption

![RadTreeView Custom Attributes](https://www.telerik.com/products/aspnet-ajax/documentation/assets/4e7a44244f53473eef43bf7b3f470acd/treeview_customattribute1.png)

```ASPNET
<telerik:RadTreeView RenderMode="Lightweight" ID="RadTreeView1" runat="server" OnNodeClick="RadTreeView1_NodeClick">
    <Nodes>
        <telerik:RadTreeNode runat="server" ExpandMode="ClientSide" Text="Red Oak" ScientificName="Quercus rubra">
        </telerik:RadTreeNode>
        <telerik:RadTreeNode runat="server" ExpandMode="ClientSide" Text="Eastern Red Cedar"
            ScientificName="Juniperus virginiana">
        </telerik:RadTreeNode>
        <telerik:RadTreeNode runat="server" ExpandMode="ClientSide" Text="Lacebark Elm" ScientificName="Ulmus parvifolia ">
        </telerik:RadTreeNode>
    </Nodes>
</telerik:RadTreeView>
```

```C#
protected void RadTreeView1_NodeClick(object sender, Telerik.Web.UI.RadTreeNodeEventArgs e)
{    
    e.Node.Text = e.Node.Attributes["ScientificName"];
}
```

```VB.NET
Protected Sub RadTreeView1_NodeClick(ByVal sender As Object, ByVal e As Telerik.Web.UI.RadTreeNodeEventArgs)
    e.Node.Text = e.Node.Attributes("ScientificName")
End Sub
```

> caution The custom attribute's name should not be an **HTML reserved word** . Please see [this article](https://www.telerik.com/products/aspnet-ajax/documentation/controls/treeview/troubleshooting/custom-attributes) for more information.

## See Also

* [Custom Attributes](https://www.telerik.com/products/aspnet-ajax/documentation/controls/treeview/troubleshooting/custom-attributes)