First, you need to specify for each button which article is it for, you can easily do it with data- attribute
<button class="votebutton" data-article="1" data-vote="1">Up vote</button>
<button class="votebutton" data-article="1" data-vote="-1">Down vote</button>
<span class="votes" data-article="1"><?=//print the current number of votes of this article//?>
Now you need to do something when the button is clicked, so your javascript would look something like that:
$('.votebutton').on("click", function(){
vote = $(this).attr("data-vote");
article = $(this).attr("data-article");
rateArticle(vote, article);
})
now you need the rateArticle() function that would look something like this:
function rateArticle(vote, article){
var data = 'vote='+rating+'&articleID='+article;
$.ajax({
type: 'POST',
url: 'rateArticle.php',
data: data,
success: function(votes){
$('.vote[data-article='+article+']').html(votes);
}
});
}
on the server side, the rateArticle.php file that you'll post to would look something like this:
$vote = $_POST['vote'];
$articleID = $_POST['articleID'];
$currentVotes = ; //fill it with the votes that the article currently have
if($vote != "-1" || vote != "1"){
//goddamn script kids messing with us again, let's put them back where they belong
header("Location: http://www.lemonparty.com"); //probably not this, but you can think of something
}
if(userHasAlreadyVoted()){ //if user has already voted we just return the current number of votes
echo $currentVotes;
}else{
$newVotes = $currentVotes + $vote;
//save newVotes to db...
echo $newVotes;
}
And that's about it...