How to specify javascript to run when ModalPopupExtender is shown | The ASP.NET AJAX **ModalPopupExtender** has `OnCancelScript` and `OnOkScript` properties, but it doesn't seem to have an `OnShowScript` property. I'd like to specify a javascript function to run each time the popup is shown.


In past situations, I set the `TargetControlID` to a dummy control and provide my own control that first does some JS code and then uses the JS methods to show the popup. But in this case, I am showing the popup from both client and server side code.


Anyone know of a way to do this?


BTW, I needed this because I have a textbox in the modal that I want to make a TinyMCE editor. But the TinyMCE init script doesn't work on invisible textboxes, so I had to find a way to run it at the time the modal was shown