You will have to make a second button for down voting. Give the upvote button a class of up and the down vote button a class of down.
jQuery
<?php wp_enqueue_script( 'jquery' ) ?>
<?php wp_head(); ?>
<script type="text/javascript">
jQuery(document).ready(function() {
jQuery(".vote a.up").click(
function() {
var some = jQuery(this);
var thepost = jQuery(this).attr("post");
var theuser = jQuery(this).attr("user");
jQuery.post("<?php bloginfo('template_url'); ?>/vote.php", {
user: theuser,
post: thepost,
updown: 'up'
}, function(data) {
var votebox = ".vote" + thepost + " span";
jQuery(votebox).text(data);
jQuery(some).replaceWith('<span class="voted">Voted</span>');
});
});
jQuery(".vote a.down").click(
function() {
var some = jQuery(this);
var thepost = jQuery(this).attr("post");
var theuser = jQuery(this).attr("user");
jQuery.post("<?php bloginfo('template_url'); ?>/vote.php", {
user: theuser,
post: thepost,
updown: 'down'
}, function(data) {
var votebox = ".vote" + thepost + " span";
jQuery(votebox).text(data);
jQuery(some).replaceWith('<span class="voted">Voted</span>');
});
});
});
</script>
vote.php
<?php
$file = dirname(__FILE__);
$file = substr($file, 0, stripos($file, "wp-content") );
require( $file . "/wp-load.php");
$currentvotes = get_post_meta($_POST['post'], 'votes', true);
if("up" == $_POST['updown']) {
$currentvotes ++;
} elseif("down" == $_POST['updown']) {
$currentvotes --;
}
$voters = get_post_meta($_POST['post'], 'thevoters', true);
if(!$voters) $voters = $_POST['user']; else $voters = $voters.",".$_POST['user'];
update_post_meta($_POST['post'], 'votes', $currentvotes);
update_post_meta($_POST['post'], 'thevoters', $voters);
echo $currentvotes;
?>
Thats all you should need to edit