function changeDisplayElement(AElement, ADisplay){
  AElement.style.display = ADisplay;
}

function changeDisplayById(AId, ADisplay){
  changeDisplayElement(document.getElementById(AId), ADisplay);
}

function changeDisplayByArray(AArray, ADisplay){
  for (var i = 0; i < AArray.length; i++){
    changeDisplayById(AArray[i], ADisplay);
  }
}

function changeDisplay(AElement, AFindTag, ARegExp, ADisplay, AToggle, ADisplayElement){
  var the_element = window.document.getElementById(AElement);
  var the_childElements = the_element.getElementsByTagName(AFindTag);
  var the_regExp = new RegExp(ARegExp);
  for (i = 0; i < the_childElements.length; i++) {
    if ((AToggle != '') && (the_childElements.item(i).id == AToggle)) {
      if ((ADisplayElement == 'block') || (ADisplayElement == 'none')) {
        changeDisplayElement(the_childElements.item(i), ADisplayElement);
      } 
      else {
        toggleDisplay(the_childElements.item(i));
      }
      
    } else if (the_regExp.test(the_childElements.item(i).id) == true) {
        the_childElements.item(i).style.display = ADisplay;
      }
  }
}

function toggleDisplay(AElement){
  if (AElement.style.display == 'block') {
    AElement.style.display = 'none';
  } else {
    AElement.style.display = 'block';
  }
}

function toggleDisplayById(AId){
  var the_element = document.getElementById(AId);
  toggleDisplay(the_element);
}