$username=$_POST['username'];
else{
$username = strtolower($username);
$sql_cek="SELECT * FROM user WHERE id_user='$username'";
$qry_cek=mysql_query($sql_cek);
$jum_cek=mysql_num_rows($qry_cek);
if ($jum_cek >= 1) {
echo "E-MAIL <BLINK><b>$username</b></BLINK> SUDAH PERNAH DIGUNAKAN";
echo "<br> SILAHKAN GUNAKAN YANG LAIN";
header('Refresh: 3; URL=index.php');
exit;
}