Every object that has an interactivity style can have an associated custom script attribute. This attribute specifies custom script to be injected in the page containing the control when used in Web applications. The custom script attribute is represented by the NCustomScriptAttribute class. You assign a custom script to the object by creating an instance of this class and adding it to the InteractivityAttributes collection. For example:

NCustomScriptAttribute customScript = new NCustomScriptAttribute();
customScript.JScript = "some JScript";
someObject.InteractivityStyle.InteractivityAttributes.Add(customScript);

Dim customScript As New NCustomScriptAttribute
customScript.JScript  = "some JScript"
someObject.InteractivityStyle.InteractivityAttributes.Add(customScripts)