eventtracking.js

<script>

//#function
function track_event(category, action, label)
{
    if(window.pageTracker) {
        pageTracker._trackEvent(category, action, label);
    }
}

//# use.
$('#green-buy-btn').click(function(
    track_event('Landing Page', 'Buy Button Clicked','Green Button');
));

$('#blue-buy-btn').click(function(
    track_event('Landing Page', 'Buy Button Clicked','Blue Button');
));

</script>