How do i collapse data i pulled out of mysql? I have a messaging system that shows all messegse between you and another member.

<table border='1' width='100%'>
                $ID = $_COOKIE['idCookie'];
                $memberid = $_GET['id'];
                $query = mysql_query("SELECT * FROM `private_messages` WHERE to_id='$ID' AND To_Deleted='0' AND from_id='$memberid' OR to_id='$memberid' AND from_id='$ID' ORDER BY id ASC");
                while($row = mysql_fetch_assoc($query)){
                $subject = $row['subject'];
                $toid = $row['to_id'];
                $read = $row['opened'];
                $fromid = $row['from_id'];
                $messageid = $row['id'];
                $message = $row['message'];
                $message = str_replace($smile_symble, $smile_pic, $message);
                $message = preg_replace('/\-(.*)\-/', '<s>$1</s>', $message);
                $message = preg_replace('/\_(.*)\_/', '<u>$1</u>', $message);
                // The Regular Expression filter
                $reg_exUrl = "/(http|https|ftp|ftps)\:\/\/[a-zA-Z0-9\-\.]+\.[a-zA-Z]{2,3}(\/\S*)?/";
                // The Text you want to filter for urls
                $text = $message;
                // Check if there is a url in the text
                if(preg_match($reg_exUrl, $text, $url)){
                    // make the urls hyper links
                    $text = preg_replace($reg_exUrl, "<a href='{$url[0]}'>{$url[0]}</a>", $text);
                    $message = $text;
                    // if no urls in the text just return the text
                    $message = $text;
                $check_pic = "members/$fromid/image01.jpg";
                $query2 = mysql_query("SELECT * FROM `members` WHERE id LIKE '$fromid'");
                            while ($row = mysql_fetch_assoc($query2)){
                            $firstname = $row['firstname'];
                            $lastname = $row['lastname'];
                    $user_pic ="<img src=\"$check_pic\" width=\"75\" heign='75'>";
                        $user_pic ="<img src=\"$default_pic\" width=\"75\" heign='75'/>";
                    echo "<tr>
                    <td width='75'><a href='$fromid'>$user_pic</a></td>
                    <td valign='top'><a href='$fromid'>$firstname $lastname</a> - <a href='messages.php?removeid=$messageid&fwd=$fwd'>Delete</a></br><hr>$message</td>
                $update = mysql_query("UPDATE `private_messages` SET opened='1' WHERE to_id='$fromid' AND from_id='$toid'");
                <td colspan='2' align='center'>
                    <form action='messages.php?Box=messagebox&id=<?php echo $memberid ?>' method='post' name="bottom">
                    <textarea id='Msg' name='Msg' cols='50' rows='4'></textarea></td></tr>
                    <tr><td colspan='2' align='right'>
                    <input name='parse_var' type='hidden'  value='Message'/>
                    <input type='submit' value='send'/></td></tr></table>

How would i collapse the data being shown on the screen so if there's say 5 messeges. When it get's to six. the top 5 will be collepsed and hidden. but the 6th one will show. so it shows there's something there. But its like "minimized" And when they click on the collapsed data it expands and shows the text in the messages.

But with the collapsed data. The last message stills shows.