Simple way to Rate your post without wordpress plugin

in single post insert the code below.

<form method='POST' action="">
<input type=hidden name=rate value=up>
<input type=submit value=submit>
</form>



<?php
if(isset($_POST['rate'])) {
if($_POST['rate']=='up') {
$rate=get_post_meta($post->ID,'up',true);
$rate=$rate+1;
update_post_meta($post->ID,'up',$rate);
}
if($_POST['rate']=='down') {
$rate=get_post_meta($post->ID,'down',true);
$rate=$rate+1;
update_post_meta($post->ID,'down',$rate);
}
}
echo "UP:".get_post_meta($post->ID,'up',true);
echo "DOWN:".get_post_meta($post->ID,'down',true);
?>

I hope you will have idea about it.

decorate submit button up and down with some backgound image like thumb down and thumb up image.

to filter top rated post use the query given below.

query_posts('&meta_key=up&orderby=meta_value_num&order=DESC');