I have assigned the code to display the text and button in the middle of the page vert and horiz but it's only centering it in horiz but not vert. why?
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="index.aspx.cs" Inherits="_Default" Culture="ar-BH" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html dir="rtl" lang="ar-bh" xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>Untitled Page</title>
</head>
<body dir="rtl" lang="ar-bh" bottommargin="5" leftmargin="5" rightmargin="5" topmargin="5">
<form id="form1" runat="server">
<table align="center" height="100%" width="100%" border="0" cellpadding="0" cellspacing="0" dir="rtl" lang="ar-bh">
<tr>
<td align="center" valign="middle" width="100%" height="100%">
أهلا بكم في مركز استطلاع الرأي<br /><br />
<asp:Button ID="btnRegister" runat="server" Text="دخول المشتركين" /> <asp:Button ID="btnLogin"
runat="server" Text="مشترك جديد" /></td>
</tr>
</table>
</form>
</body>
</html>