page1.php
===========================================================================

<?php

require_once 'testclass.php';
$tc = new TestClass;

?>
<html>
<body>

<?php

$tc->display();
$str = htmlspecialchars( serialize( $tc ) );
echo "\$str = $str<br>\n";

?>

<form method = "post" action = "page2.php">
	<input type = "hidden" name = "str" value = "<?php echo $str; ?>">
	<input type = "submit" value = "next page">
</form>
</body>
</html>

===========================================================================


page2.php
===========================================================================

<?php

require_once 'testclass.php';

$str = stripslashes( htmlspecialchars_decode( $_POST["str"] ) );
$tc = unserialize( $str );

?>
<html>
<body>

<?php

$tc->display();
echo "\$str = $str<br>\n";

?>

</body>
</html>

===========================================================================


testclass.php
===========================================================================

<?php

class TestClass {
	var $i = 5;
	var $j = 'This is a "test" string';

	function display() {
		echo "i=" . $this->i . "<br>\n";
		echo "j=" . $this->j . "<br>\n";
	}
}

?>

===========================================================================