Whats wrong with this simple php script?

[Justin Sampson]

Hi,
Can Anyone tell me whats wrong with this script? I'm trying to get it so when you go to http://www.domain.com/delete.php3?id=2 it will delete the article with the ID of 2 when you click the button. Here's the code I have. It doesn't give me any errors but it doesn't do anything either

<?php
 
  if ("SUBMIT" == $deletearticle) {
   $sql = "DELETE FROM articles WHERE ID=$id ";
   
   if (mysql_query($sql)) {
   echo("<P>Your article has been deleted.</P>");     
    } else {    
	echo("<P>Error deleting article: " .
mysql_error() . "</P>");      
}
}
?>
<form ACTION="<?php echo($PHP_SELF); ?>" METHOD=POST>
<INPUT TYPE=HIDDEN NAME="id" VALUE="<?php echo($id); ?>">
<INPUT TYPE=SUBMIT NAME="deletearticle" VALUE="Delete">
</form>

Thanks,
Justin Sampson