一个提交表单的重定向问题

我这个文件验证成功想提交到echo "<script>window.location='reg.php?username="&$_POST['username']&"password="&$_POST['password']&"';</script>";这个页面，这段代码怎么提交不过去，还是当前页面？
<?php
session_start();
if (!empty($_SESSION['num']) and !empty($_SESSION['num']) and $_SESSION['num']==$_POST['number']){//验证
echo "<script>alert('成功');windows.close();</script>";
echo "<script>window.location='reg.php?username="&$_POST['username']&"password="&$_POST['password']&"';</script>";
}else{
echo "失败";
}
?>
<form method="post" action="<?=$_SERVER['PHP_SELF']?>">
<table width="255" border="0" align="center" cellpadding="6">
<tr>
<td>用户名： </td>
<td><input name="username" type="text" size="15" /></td>
<td> </td>
</tr>
<tr>
<td>密　码：</td>
<td><input name="password" type="text" size="15" /></td>
<td> </td>
</tr>
<tr>
<td>验证码：</td>
<td><input name="number" type="text" size="15" /></td>
<td><img src="image.php" alt="验证图" /></td>
</tr>
<tr align="center">
<td colspan="3"> <input type="submit" name="submit" value="提交" />　
<input type="submit" name="submit" value="取消" /></td></tr>
</table>
</form>