[solved] select html element and click?

[gin]

I'm trying to select certain elements on the comment section to post a comment on the url below
http://thechive.com/2014/01/13/beagle-g ... ets-video/

I can identity the elements using firebug addon for firefox, but how do I click them?

The first one is to enter my comment...

<span class="placeholder">Join the discussion…</span>


The second one is to post...

<span>

Username

</span>


Thanks