var vHeight = 0;
if (document.all) {
  if (document.documentElement) {
    vHeight = document.documentElement.clientHeight;
  } else {
    vHeight = document.body.clientHeight
  }
} else {
  vHeight = window.innerHeight;
}

if (document.body.offsetHeight > vHeight) {
  //insert code for whatever happens
  //when theres a scrollbar
document.write ('</div><div id="botter_r">');  
}
else {
document.write ('</div><div id="botter_a">');  
}