How do I call a function when bootstrap collapse expands

Question

I want to activate this javascript:

jsPlumb.repaintEverything();

...and fire up an alert box saying "I'm expanding!!!" when a user clicks the button in this fiddle

Does anyone know how to achieve this?

Answer 1

You can use the shown.bs.collapse event that Bootstrap raises:

$('#demo').on('shown.bs.collapse', function() {
    jsPlumb.repaintEverything();
});

Updated fiddle

Note that this event fires after the element expansion animation has completed. If you want to run the code as the animation starts, use show.bs.collapse instead