getData() Problems

Hi, I'm currently using Ckeditor for posting blogs to a site, and also for editing original posts.
However, when I try and edit the post and update the content via AJAX, using getData(), any apostrophes I put in come back as "'", is this meant to happen? I don't know how I can convert them in PHP, does it have a special function for this?
I've tried html_entity_decode and htmlspecialchars_decode but having no luck.

Can anyone tell me where I'm going wrong?

<input type="button" value="Update" onclick="updateTextarea(CKEDITOR.instances.editortextarea.getData(), <?php echo $post[0]; ?>);"/>

Calls this function:

function updateTextarea(text, id) {
   if(text != '') {
      alert(text);
      $('#textareaupdate').html('Updating...');
      $('#textareaupdate').show();
      $.ajax({  
      type: "POST",  
      url: "edit.php",  
      data: 'textarea=' + text + '&id=' + id + '&mode=text',  
      success: function(msg) {
            if(msg == 'fail')
               $('#textareaupdate').html('Failed to update content :(');
            else {
               $('#textareaupdate').html('Done!');
            }
            alert(msg);
            setTimeout(function () {
               $('#textareaupdate').hide();
            }, 2000);
         }
         
      });
   }
}

Which goes to:

else if(isset($_POST['textarea']) && $_POST['textarea'] != '' && isset($_POST['id']) && is_numeric($_POST['id']) && isset($_POST['mode']) && $_POST['mode'] == 'text') {
   if($text = str_replace('src="../ckfinder', 'src="ckfinder', $_POST['textarea'])) {
      $text = html_entity_decode($text);
   }
   else {
      $text = html_entity_decode($_POST['textarea']);
   }
   $text = mysql_real_escape_string($text);   
   $id = mysql_real_escape_string($_POST['id']);
   if(!$update = mysql_query("UPDATE `blog` SET `content` = '{$text}' WHERE `id` = {$id} "))
      echo 'fail';
}

Any help is greatly appreciated,

Thanks.

Edit: Any alerts I've put in there are just for debugging purposes, so I can see what's going where.