When you step through with the debugger, what does mydiv.ClientID resolve to? how does that compare to what's shown when you view the source of the rendered page?

I think a couple of controls you should study that will give you ideas about how to work with javascript in your own controls and features are:

• TwitterWidget.cs - a server control that inherits from <asp:Panel and wires itself up to the div that panel renders as using ClientID and it shows how to build up a script using StringBuilder. It has 2 scripts, it shows how to include a main script from twitter and StringBuilder is used to wire up the instance of the widget to the div
• SkinSetting.ascx.cs a UserControl example it builds some javascript to wireup a preview link for the skins listed in the <asp:DropDownList, see also the SkinSetting.ascx file that has the <asp:DropDownList

Hope that helps,

Joe

No, you should design your main javascript so that you pass in the ids for elements, and then use a smaller script rendered in the control to invoke your main script. So your main script can be external but it can't have any dependencies on things in your page or control, you have to pass that stuff in.

like jquery ui widgets are implemented in external files, then you only need a small script in the control to wire up a jquery widget using a selector with ids from your control.

Hope that helps,

Joe