Als erstes die Function
function FrameAendern (URI, Framename) {
parent[Framename].location.href = URI;
und dann die Anweisung
<td width="140" height="53"> <a href="home.html" target="mainFrame" onClick="MM_nbGroup('down','navbar1','Button20Home','Button%20Home_f3.gif',1);" onMouseOver="MM_nbGroup('over','Button20Home','Button%20Home_f2.gif','Button%20Home_f3.gif',1);" onMouseOut="MM_nbGroup('out');"><img name="Button20Home" src="Button%20Home.gif" width="110" height="25" border="0" alt=""></a> </td>
<td width="140"> <a href="Braukunst/braukunst.html" target="mainFrame" onClick="MM_nbGroup('down','navbar1','Button20Braukunst_2','Button%20Braukunst_f3.gif',1);FrameAendern('Braukunst/Braugeschichte/Braugeschichte.htm','iframe')" onMouseOver="MM_nbGroup('over','Button20Braukunst_2','Button%20Braukunst_f2.gif','Button%20Braukunst_f3.gif',1);" onMouseOut="MM_nbGroup('out');"><img name="Button20Braukunst_2" src="Button%20Braukunst.gif" width="110" height="25" border="0" alt=""></a> </td>
<td width="140"><a href="javascript:;" target="_top" onClick="MM_nbGroup('down','navbar1','Button20Ueber20uns','Button%20Ueber%20uns_f3.gif',1);" onMouseOver="MM_nbGroup('over','Button20Ueber20uns','Button%20Ueber%20uns_f2.gif','Button%20Ueber%20uns_f3.gif',1);" onMouseOut="MM_nbGroup('out');"><img name="Button20Ueber20uns" src="Button%20Ueber%20uns.gif" width="110" height="25" border="0" alt=""></a>
</td>