function ShowHide(elementId) {
  var element = document.getElementById(elementId);
  if (element) {
    if (!element.style.display) element.style.display = "none";
    if (element.style.display == "" || element.style.display == "none") {
      element.style.display = "block";
    } else { 
      element.style.display = "none";
    }
  }
}