Php echo command does not work in Highslide "html content" Can you help please?

Php echo command does not work in Highslide "html content" Can you help please?

<?php include ("css/servis.php");?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />

<link rel="stylesheet" type="text/css" href="highslide/highslide.css" />
<script type="text/javascript" src="highslide/highslide-full.js"></script>
<script type="text/javascript" src="highslide/highslide.config.js" charset="utf-8"></script>


<link rel="stylesheet" type="text/css" href="css/jquery.autocomplete.css" />
<script src="js/jquery.js"></script>
<script src="js/jquery.autocomplete.js"></script>

<script type="text/javascript">
    var jq=$.noConflict();
    jq().ready(function() {
    jq("#secim").autocomplete("projeal.php", {
    width: 500,
    matchContains: true,
    selectFirst: false
    });
    });
</script>   

</head>
<body>
   
<div id="content">
        <form autocomplete="off" method="post" action="">Insert Proje Name <label>:</label>
        <input type="text" name="gelen" id="secim"  size="80"/>
       
        <input type="submit" value="Submit" 
        onclick="return hs.htmlExpand(this, {width: '800',headingText:'',wrapperClassName: 'titlebar'})"/>
       
            <div class="highslide-maincontent">
                <?php
                $projeno="";                       
                $aldi="";
                if ($_POST){
                    $aldi = $_POST["gelen"];
                    $bul = mysql_query("SELECT * FROM projeler ORDER BY yyili DESC");
                    $ksayi = mysql_num_rows($bul);
                    while ($goster = mysql_fetch_array($bul)){
                   
                        if (trim($aldi) == trim($goster['padi'])){
                            $projeno = $goster['pno'];
                            echo $projeno;
                        }
                    }
                }
                ?>
               
            </div>
        </form>
</div>

</body>
</html>

// Php echo command  does not work in Highslide "html content"
// Can you help please?