Q:

Passing an Object between PHP pages, IDE and passing object to other classes problems

I've inherited some PHP code that I need to make significant changes on.  I know with PHP it is possible to serialize an Object, and pass the serialized text between pages as FormData.  In the code I've inherited, they have done just that, But this is creating some maintainability problems.  I'm wondering if taking this approach is even a good idea.
For example ...
When the user opens PageA.php the following is created: 
$expensiveObj = new ExpensiveClass($id);

The $expensiveObj is then serialized and the resulting text is stored in a div with the following:
<div id="expensiveObj"><?php echo strtr(base64_encode(serialize($expensiveObj)), '+/=', '-_,');?></div>

When PageA.php loads, an ajax call is made to PageB.php.  The content of the div is passed along as a post variable to PageB.php.  Within PageB.php the following code unserializes the  object:
$expensiveObj = unserialize(base64_decode(strtr($_POST['expensiveObj'], '-_,', '+/=')));  

The fields and methods of the $expensiveObj are now accessible to PHP.  The problems I'm encountering are 

Because the $expensiveObj is not identified in PageB.php as an instance of the Class ExpensiveClass then the IDE doesn't know that the fields and functions of ExpensiveClass are available.  I can't do autocomplete, nor lookup within the IDE what functions are available.  Plus the IDE can't catch potential issues.  The other developer worked exclusively in VI, so he never cared.
PageB.php needs to be re-factored.  There is view, business, and controller logic all happening within this page, I would prefer to create a couple of classes, but I'm encountering a problem where I don't know how to pass the $expensiveObj to a class.  

My questions are, is there a way to pass an Object to a class? And is there a way inform the IDE that the passed in post variable is indeed an instance of ExpensiveClass?  
Lastly, is it even a good idea to be passing around objects this way, or should I be looking at a larger re-factor? 

A:

Storing objects directly in HTML is never a good idea, because it can be easily changed by client. In PHP is more common to create new object on every request according to given parameters. I see you are initializing your object using $id, so you can just pass this id between requests. Storing data to session also isn't best practice, session should be used for session-specific data, e.g. logged-in user etc.
If the creation of the object is very expensive, you can use cache, e.g. memcache, some external library or just to write your own, for example storing data in JSON on file system or in database.

