How to add js only when widget contains a special shortcod

Hi everybody,
I need a solution for having a problem with widgets, shortcodes and javascript. I use the normal text widget in my sidebar which can display different shortcodes. What I cannot figure out how I can add a javascript only if there is the shortcode inside the widget?

For getting this to work if a shortcode is inside the post content isn’t the problem, but how can I do it with widget’s content?

Thanx in advance!