Add a counter for mouseovers (custom field)

I am trying to count mouseovers on the div for each post. The div is inside the loop. I am almost there, I think you might have to just help me correct some mistake.

The div and jquery. Notice that I am using the the_ID() to give the div an CSS id, which this allows the Jquery to target it. It uses AJAX to pass the post id to addHit.php

<div class="loop-entry-details" id="post<?php echo the_ID() ?>">
<script> 
$('#post<?php echo the_ID() ?>').mouseover(function(){   
    postID = <?php echo the_ID() ?>;
    $.ajax({
        type: "POST",
        url: "addHit.php",
        data:{ post_id: postID }, 
        success: function(data){
            console.log(data); 
        }
    })
}
</script>
</div>

addHit.php located in the theme root

$post_id = $_POST['post_id'];

function addHit2($post_id){
$key = 'hits';
$themeta = get_post_meta($post->ID, $key, TRUE);


if($themeta != '') {
    add_post_meta($post_id, $key, 1);
} else {
    update_post_meta($post_id, $key, 1);
}
    }
addHit2($post_id);

Doesn't seem to work. What's wrong?