сделал вот так: (все равно не работает)
<html>
<head>
<link rel="stylesheet" href="css/bootstrap.css" type="text/css"/>
<script type="text/javascript" src="js/jQuery.js"></script>
<script type="text/javascript" src="js/bootstrap.js"></script>
<script>$('#demo').collapse('toggle');</script>
</head>
<body>
<button class="btn btn-danger" data-toggle="collapse" data-target="#demo">
simple
</button>
<div id="demo" class="collapse in"> !!!!!!!!!!!!!!!!!!!!!!!!!! </div>
</body>
</html>