Voting system with jQuery, Ajax and PHP works only local server

Question

I am a no good in PHP (just learning). I tried modifying a php voting script which I downloaded from a free source. i can add image though (it was not an easy task for me and I am not done yet). Now Voting works fine on my local server , but online it doesn't. If I click to vote, the numbers just disappear without return. below are the codes to look into.

index.php ---

<?php include('config.php'); 

$sql=mysql_query("SELECT * FROM messages ORDER BY `messages`.`up` DESC LIMIT 20"); 

while($row=mysql_fetch_array($sql)) { $title=$row['title']; $desc=$row['desc']; 

$mes_id=$row['mes_id']; $image=$row['image']; $up=$row['up']; 

$down=$row['down']; ?> <div id="vote"> <div class="box1"> 
<div class='up'><a href="" class="vote" id="<?php echo $mes_id; ?>" name="up"> 
<?php echo $up; ?></a></div> 

<div class='down'><a href="" class="vote" id="<?php echo $mes_id; ?>" name="down">
<?php echo $down; ?></a></div></div> 

<div class='image' ><?php echo "<img src=user/admin/".$image ." width='87%' height='70%'/>"?></div> 

<div class ='title'><?php echo $title; ?></div> 

<div class='box2' > 
<?php echo $desc; ?> </div> </div> 

<?php } ?>

up_vote.php --------------------------

<?php include("config.php"); 

$ip=$_SERVER['REMOTE_ADDR']; 
if($_POST['id']) { $id=$_POST['id']; $id = mysql_real_escape_String($id); $ip_sql=mysql_query("SELECT ip_add FROM voting_ip WHERE mes_id_fk='$id' AND ip_add='$ip'"); 

$count=mysql_num_rows($ip_sql)or die(mysql_error()); 
if($count<=20) 
{ 
$sql = "UPDATE messages SET up=up+1 WHERE mes_id='$id'"; mysql_query( $up); 
$sql_in = "INSERT INTO messages (mes_id_fk,ip_add) VALUES ('$id','$ip')"; mysql_query( $sql_in); 
} else 
{ echo "<script>alert('You have already voted');</script>"; } 
$result=mysql_query("SELECT up FROM messages WHERE mes_id='$id'"); 
$row=mysql_fetch_array($result); $up_value=$row['up']; echo $up_value; } ?> 

down_vote.php -----------------------------

<?php include("config.php"); 

$ip=$_SERVER['REMOTE_ADDR']; 
if($_POST['id']) { $id=$_POST['id']; 
$id = mysql_real_escape_String($id);

 $ip_sql=mysql_query("SELECT ip_add FROM voting_ip WHERE mes_id_fk='$id' AND ip_add='$ip'"); 

$count=mysql_num_rows($ip_sql) or die(mysql_error());
 if($count<=0)

 { $sql = "UPDATE Messages SET down=down+1 WHERE mes_id='$id'"; mysql_query( $sql); 
$sql_in = "INSERT INTO voting_ip (mes_id_fk,ip_add) values ('$id','$ip')"; mysql_query( $sql_in); 
} else { echo "<script>alert('You have already voted');</script>"; } 

$result=mysql_query("SELECT down FROM Messages WHERE mes_id='$id'"); 
$row=mysql_fetch_array($result); 
$down_value=$row['down']; echo $down_value; } 
?>

Javascript --------------------------- (this is at the index header with some HTML codes)

<script type="text/javascript">
$(function() {

$(".vote").click(function() 
{

var id = $(this).attr("id");
var name = $(this).attr("name");
var dataString = 'id='+ id ;
var parent = $(this);


if(name=='up')
{

$(this).fadeIn(200).html('<img src="dot.gif" align="absmiddle">');
$.ajax({
   type: "POST",
   url: "up_vote.php",
   data: dataString,
   cache: false,

   success: function(html)
   {
    parent.html(html);

  }  });

}
else
{

$(this).fadeIn(200).html('<img src="dot.gif" align="absmiddle">');
$.ajax({
   type: "POST",
   url: "down_vote.php",
   data: dataString,
   cache: false,

   success: function(html)
   {
       parent.html(html);
  }

 });


}


return false;
    });

});
</script>

I appreciate anyone helping out, thanks everyone.

Answer 1

From your code,

if($count==50)

then only the values are being updated!!. How is it possible for a person who is going to vote for the first time??? It should be

if($count<50)

Answer 2

Going to take a wild stab here but 9/10 'It works locally but not on live' issues are either php version mismatches or differences in Apache config (differing module configurations etc) presuming LAMP.

Check the php versions match and if they don't check the change logs to detect any functions that do not work within both. This is likely the issue.

And as commented above. Always check your server logs.