[Javascript] Font size control bar

[Barry Conner]

I've created the following little view control bar which I designed to display in a frames navigation window for my HTML-based application interface.  The frame is generated as a popup to exclude all of the undesirable toolbar & status bar overhead.
 
The actual font manipulation here is handled via a set of JS & CSS files (as posted at http://www.alistapart.com/articles/relafont )
 
HERES THE QUESTION:  This is intended as a mere view control bar, so how might I script the fontsize controls to act on the main frame rather than on itself???
 
Thanks for any thoughts you might have on a solution!
 
Barry
 
<!--~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~-->
<form name="font_select" action="GET">
     <table align="center" width="100%" location="0" cellspacing="0" cellpadding="4" rules=cols frame=below border="1" margins="0">
          <tr>
               <td width="25%">
                    <strong>
                    View Control:
                    </strong>
               </td>
               <td align="center">
                    <button type="button" onclick="javascript:history.back()"><small>&nbsp;&nbsp;Back&nbsp;&nbsp;</small></button>
               </td>
               <td align="center">
                    <button type="button" onclick="javascript:history.forward()"><small>Forward</small></button>
               </td>
               <td align="center">
                    <button type="button" onclick="javascript:fontsizedown();"
                    value=" font - " />
                    <small>Smaller Font</small></button>
               </td>
               <td align="center">
                    <button type="button" onclick="javascript:fontsizereset()" />
                    <small>&nbsp;Reset Font&nbsp;</small></button>
               </td>
               <td align="center">
                    <button type="button" onclick="javascript:fontsizeup();"
                    value=" font + " />
                    <small>&nbsp;Larger Font&nbsp;</small></button>
               </td>
          </tr>
     </table>
     <hr />
</form>
<!--~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~-->