Firefox changes table's CSS

[globex]

After using Javascript to set display to none and then back to block, Firefox changes the width of my table. This doesn't happen in IE. Any ideas?

You can see this in effect at:

http://www.naverniouk.com/school.php

Press and "Hide" and "Show" buttons.

[globex]

Fixed.

Had to change the width of the table td from 80% to 400px (a fixed value).