miren lo tengo asi:
<script>
function foro (){
arriba.location.href="foro1.htm";
centro.location.href="foro2.htm";
}
function link (){
arriba.location.href="link1.htm";
centro.location.href="link2.htm";
}
</script>
<iframe name="arriba" src="iframearriba.htm" frameborder="0" height="40" width="535" scrolling="no"></iframe>
<br><br>
<iframe name="centro" src="iframecentro.htm" frameborder="0" height="40" width="535" scrolling="no"></iframe>
<br><br>
<a href="#" onClick="foro()">Foros</a>
<br>
<a href="#" onClick="link()">Links</a>
<br>
<a href="javascript
:history.back(2)">Atras</a>
<br>
<a href="javascript
:arriba.history.go(-2); centro.history.go(-2);">Atras2</a>