cnt = document.getElementById("content" );
  sb1 = document.getElementById("sidebar1");
  sb2 = document.getElementById("sidebar2");
  if ((sb1 && cnt.clientHeight < sb1.clientHeight) || (sb2 && cnt.clientHeight < sb2.clientHeight)) {
    if (sb2) { cnt.style.height = (sb1.clientHeight>sb2.clientHeight?sb1.clientHeight:sb2.clientHeight) +'px'; }
    else { cnt.style.height = sb1.clientHeight +'px'; }
  }