Great script grue, thanks!
Just a little thing though, when I tried installing and using the script it would tell me 'Failed to give merit' whenever I tried to reward it. I found that this was a session error due to how you get 'sc'.
I've made a small fix here (on lines 12-14), which works for me currently:
//get csrf token
var sc = $('input[name="sc"][type="hidden"]').val();
sc = (!sc ? ($('a[onclick]')[1].href).split('sesc=')[1] : sc);