Collapse show/hide/toggle methods don't work while a previous animation is still running

Created by: MiladSadinam

Using

$('.collapse').collapse('show');
$('.collapse').collapse('hide');

ends up in state 'show'. The second collapse() is being ignored because the first animation is still running.

https://jsfiddle.net/fjb5r9s5/2/ demonstrates that clicking quickly the button results in wrong states.

I could reproduce this in the current versions of Chrome, Firefox and IE.

EDIT: Fixed HTML5 Validator error