jquery - icon up and down with accordion bootstrap -

i try make icon chevron down , accordion bootstrap :

i have :

http://jsfiddle.net/hwnyb/18/

i try js it's doesn't work :

<script type="text/javascript">  $('.accordion').on('show hide', function (n) {     $(n.target).siblings('.accordion-heading').find('.accordion-toggle i').toggleclass('icon-chevron-up icon-chevron-down'); }); </script> 

the chevron don't when click on link.

you don't have .accordion element ?

$('.accordion-group').on('show hide', function (n) {     $(n.target).siblings('.accordion-heading').find('.accordion-toggle i').toggleclass('icon-chevron-up icon-chevron-down'); }); 

fiddle