Position Absolute when changing browser size

I've been working on a pop-up menu, one of those where you mouse over
a button and a submenu pops up. Because the client wanted the menu
centered, I gave the starting point of the submenu an absolute
position, then used relative position to place the menu where I want
it beneath the buttons. The code for the menu is posted below (in
Javascript).

Although I can't get this to happen on my computer (using IE5.0, 5.5,
and Netscape 7.0), the client says that when he changes the size of
the browser (presumably by dragging the edges), the menu doesn't
change with it. For instance, if he opens the browser maximized, the
menu looks great, but if he makes it smaller, the menu stays as if the
window were maximized.

In looking at his email, he's using Outlook Express 6.0, so I'm
guessing that he's using IE 6.0. Is there something different about
how 6.0 recognizes positioning that I should know about? If not, are
there any other suggestions?

TIA,

Mike



// The Menu Code
document.write("<center>");
document.write("<table width=\"621\" height=\"29\"><tr>");
document.write("<td><a href=\"#\" onMouseOver=\"menu(1, -50)\"
onMouseOut=\"clearIt()\"><img src="home + "buttons/1.gif\"
width=\"51\" height=\"29\" border=\"0\"></a></td>");
// 5 more cells follow
document.write("</tr></table>");
document.write("<div id=\"Menu\" style=\"position:
absolute\"></div>");
document.write("</center>");


"Menu" is defined as a table with relative positioning, based on the
variable sent to it onMouseOver. In this example, the table submenu
would be:
<table style="position: relative; top: 0px; left: -50px">