初学者问题：页面间变量值如何传递？

$connect = mysql_pconnect("localhost","root","hcedagb");
                mysql_select_db("icbcoa",$connect);
                //基本参数已经设置完成了，现在从数据库中取出总记录数
                $sql = "select count(*) as total  from oa_rizhi";    //统计记录总数
                $res = mysql_fetch_array(mysql_query($sql));
                $countAll = $res['total'];                $sql = "select * from oa_rizhi where riqi>'".$mdate."' order by riqi desc limit $limitFrom,$pagelist";
                mysql_query("SET NAMES 'GBK'");
                $result = mysql_query($sql);
                //$data=mysql_fetch_array($result);
                $rows = @mysql_num_rows($result);
                while($data=mysql_fetch_assoc($result))
                {
                 $riqi=$data['riqi'];
                 $neirong=$data['neirong'];
                 $sneirong = substr($neirong, 0,100);
                 $bianhao=$data['bianhao'];                ?>        <tr>                <td bgcolor="#C0C0C0">　<? echo $riqi; ?></td>
                <td width="613" bgcolor="#FFFFFF">　<? echo $sneirong; ?></td>
                <td width="61" bgcolor="#FFFFFF">&nbsp; <a href="rizhialt.php?bianhao=$bianhao">修改</td>
        </tr>
         <?
                }
                mysql_close($connect);
         ?>在修改页面中
<?
  $bianhao=$_GET["bianhao"];
  echo "$bianhao";
?>
显示不出编号值。