php - header problem

We soon notice there are some problem when using header.. because before header.. we already make output?!?
this is how to cheat the header or I think this should how to exchange header

PHP Code:

<?php if ($email==$dbemail && md5($password)==$dbpassword)
    {?>         <script type="text/javascript">
        <!--
        window.location = "member.php"
        //-->
        </script> <?
        $_SESSION['email']=$dbemail;
    }

other way is... what happen if

you client don't use javascript

try this

<noscript>
<meta http-equiv="Refresh" content="2;URL=target" />
</noscript>
<script>
window.location = "target.php";
</script>