<div id="info_id_1">
<span id="upvote_id_1" onclick="vote(1,1);">0</span> Daumen nach oben
<span id="downvote_id_1" onclick="vote(1,0);">0</span> Daumen nach unten
</div>

<div id="info_id_2">
<span id="upvote_id_2" onclick="vote(2,1);">0</span> Daumen nach oben
<span id="downvote_id_2" onclick="vote(2,0);">0</span> Daumen nach unten
</div>

<script>

function vote(id,art)
{
var atm_upvote = document.getElementById("upvote_id_"+id).innerHTML;
var atm_downvote = document.getElementById("downvote_id_"+id).innerHTML;
atm_upvote = parseInt(atm_upvote);
atm_downvote = parseInt(atm_downvote);

if(art) atm_upvote++;
else atm_downvote++;

document.getElementById("upvote_id_"+id).innerHTML = atm_upvote;
document.getElementById("downvote_id_"+id).innerHTML = atm_upvote;
}

</script>