function showCmpFile(id) {
  features='height=400,width=600,resizable=yes,status=yes,toolbar=no,menubar=no,location=no,scrollbars=yes';
  window.open('/show_cmp_file?id='+id,'nwindow',features);
}

function toggleVisible(elem) {
  toggleElementClass("invisible", elem);
}

function makeVisible(elem) {
  removeElementClass(elem, "invisible");
}

function makeInvisible(elem) {
  addElementClass(elem, "invisible");
}

function isVisible(elem) {
  // you may also want to check for
  // getElement(elem).style.display == "none"
  return !hasElementClass(elem, "invisible");
}