changing css class

[hyusetiawan]

how can I click one element to change the CSS class in another?
looking at loading states, with unicorn:loading.class, I tried
<a href="#" unicorn:click.class="expanded" unicorn:target="content_{{forloop.counter}}">view</a>
Attempting to add the class "expanded" to element with the id content_ but it does not work, I also tried unicorn:click.prevent.class

[hyusetiawan]

@adamghill ping! just want to raise this question :)