this is not perfect but maybe can help you with what you're looking for
<script type="text/javascript">
function sc(){
l.onmousemove = validatemove;
}
function validatemove(e){
px=e.pageX;
py=e.pageY;
if(px<=400 && i==0){
px=0;
}
else{
px=px-200;
}
if(py<=300 && j==0){
py=0;
}
else{
py=py-300;
}
r.scrollTo(px,py);
return false;
}
</script>
<body onload="sc();">
<iframe id="l" name="l" src="" style="width: 400px; height: 300px" ></iframe>
<iframe name="r" src="" style="width: 400px; height: 300px" scrolling="no"></iframe>