Tables in Fire Fox

I was doing a simple test and notice in Fire Fox that my table will collapse but not in I.E, I set the height to 100%, I wanted to create a table with content in the center and a style for the back ground, if you use a table do you need to make a transparent gif so F.F will not collapse the table.

My sample code:

<?xml version=“1.0” encoding=“UTF-8”?>

<!DOCTYPE html

PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"


<html xmlns=“” xml:lang=“en” lang=“en”>

&lt;body topmargin="0"&gt;

&lt;div align=center&gt;

 &lt;table style="height: 100%; width:250px; background-color: #CCC;"&gt;



    &lt;div align=center&gt;Centered Content&lt;/div&gt;