function setH() {
  var content = document.getElementById('yui-main');
  var menu = document.getElementById('secondary');
  var decoration = document.getElementById('decoration');
  

  
  var ch = content.offsetTop + content.offsetHeight;
  var nh = menu.offsetTop + menu.offsetHeight;
  

  if( ch > nh ) decoration.style.height = ( ch - nh - decoration.offsetHeight )+"px";
}
 
window.onload=setH;