How to programmatically click on facet value to filter events on a Simile Timeline Widget?

I have a facet set up thus:

<div ex:role="facet" ex:expression=".chapter" ex:facetLabel="Chapter" ex:sortMode=".count" ex:fixedOrder="1;2;3;4;5;6;7;8;9;10;11;12" ></div>

It's for filtering Chapter numbers of timeline events. How would I programmatically select one of the开发者_开发问答 facet choices to filter visible timeline events? I tried simulating a click event on the anchor in the generated HTMl, and have been unable to expose anything in the API.

The end goal is to allow filtering by chapter by getting a URL param.

http://www.jamesfishwick.com/timeline/

The attribute ex:selection can be used to pre-filter items.

I was able to add the attribute (i.e. ex:selection="3") from a param with no problems.