MSIE  = 20px
  (f11)=13px
 Opera = 17px
  (f11)=00px
 NS6   = 16px
  no vert
  scroll=00px
 NS4   = 

3 Column DIV

{display:inline} {position:relative}

{float:left} {float:left} {float:right}

Middle Column 64% of width, left 20%, right 15%   To: 1 CBE Test

The 99% maximum width is to avoid problems with an application such as AOL riding on MSIE with inner window "restore".  Too high a percentage of "average" users to ignore.  If you desire to use 100% width, suggest you FORCE "maximized screen"  howTo

Screen - Window Test Pages   demonstrates some of the differences of MSIE - NSGecko - Opera in regards to which element -?- property is used by each browser.  In this left column lists the reading I obtain from an 800x600 display for pixels devoted to vertical-scroll bar width in each of those browsers.  You can do your own check at the Screen - Window Test Pages.

It's not significant unless something such as testing for window in "restore" or "maximize" for warning with an alert - prompt to "Please Maximize Screen" for best view or test for onResize in older NSnav or Opera with positioned CSS in order to get a repaint - rewrite of screen or to get a reLoad.  Or in most browsers if magnification is changed when using positioned CSS.