# Using the TargetControlID Property

The **TargetControlID** property specifies the ID of the element that should be 'tooltipified'. It can be set declaratively on the page:

```ASP.NET
<telerik:RadToolTip RenderMode="Lightweight" ID="RadToolTip1" runat="server" TargetControlID="Button1" IsClientID="true">
</telerik:RadToolTip>
```

or in the code-behind:

```C#
Button button1 = new Button(); 
button1.ID = "Button1"; 
RadToolTip1.TargetControlID = button1.ID;
```

```VB
Dim button1 As New Button()
button1.ID = "Button1"
RadToolTip1.TargetControlID = button1.ID
```

By default, **RadToolTip** assumes a server ID. If the ID is client-side, as in the case where an element is pure HTML and not a server control, then the **IsClientID** property should be set to **True**.

```C#
Button button1 = new Button();
button1.ID = "Button1"; 
RadToolTip1.TargetControlID = button1.ClientID; 
RadToolTip1.IsClientID = true;
```

```VB
Dim button1 As New Button()
button1.ID = "Button1"
RadToolTip1.TargetControlID = button1.ClientID
RadToolTip1.IsClientID = True
```

## See Also

* [Managing Content](https://www.telerik.com/products/aspnet-ajax/documentation/controls/tooltip/radtooltip/managing-content)