var NS4 = (document.layers)?true:false;
var IE4 = (document.all)?true:false;
	
function _struct(child,childcaption,parent) {
  this.child = child;
  this.childcaption = childcaption;
  this.parent	= parent;
}

function _addobject(child,childcaption,parent) {
  var obj = new _struct();
  obj.child = child;
  obj.childcaption = childcaption;
  obj.parent = parent;
  return(obj);
}

function insertEntry(child,childcaption,parent) {
  if(child.length > 0 ) {
    for(var i=0;i<this.length;i++)
      if(this.items[i].child == child)
    return;
    this.items[this.length++] = _addobject(child,childcaption,parent);
  }
}

function OptionCollection() {
  this.length=0;
  this.items = new Object();
  this.Add=insertEntry
}

function clearSelect(oSelect) {
  var iCount=0;
  if(!oSelect) return;
  iCount = oSelect.options.length;
  for(var i=0;i<iCount;i++) {
    if(IE4)
      oSelect.options.remove(0);
    else if(NS4)
      oSelect.options[0]=null;
  }
}

function addOptions(oSelect,olist,parent) {
  var elOption;
  var idxSelect=0;

  // Check Arguments.
  if((!olist) || (!oSelect)) return;
  if(parent.length <=	0) return;
					
  // Now looop through all the list items only entering relevant options.
  clearSelect(oSelect);	
	
  // Add a blank list
  elBlankOption = new Option();
  elBlankOption.text = "";
  if(NS4) oSelect.options[0] = elBlankOption
  else if(IE4) oSelect.options.add(elBlankOption,0)
	
  elBlankOption.value = "";
  for(var i=0;i<olist.length;i++) {
    // Only the child entries of the parent
    if(olist.items[i].parent == parent) {
      elOption = new Option();
      // Now IE and NS have a different way to handle object creation.
      if(NS4) {
        elOption.value = olist.items[i].child
        elOption.text = olist.items[i].childcaption
        oSelect.options[idxSelect] = elOption
      } else if(IE4) {
        elOption.value = olist.items[i].child
        elOption.text = olist.items[i].childcaption
        oSelect.options.add(elOption,idxSelect)
      }
      idxSelect++;
      delete(elOption);
    }			
  }	
}

function clearOptions(szSelect,szForm) {
  if(szSelect.length <= 0 || szForm.length <=0)
    alert("error:clearOption must pass arguments");
  if(IE4)
    clearSelect(document.all.item(szSelect));
  else if(NS4)
    clearSelect(eval('document.' + szForm + '.' + szSelect));
}

function listAllOptions(szSelect,szForm,olist) {
  var elOption;
  var idxSelect=0;
  var oSelect = new Object();
			
  // Check arguments.
  if(!olist)return;
  if(IE4)
    oSelect = document.all.item(szSelect);
  else if(NS4)
    oSelect = eval('document.' + szForm + '.' + szSelect);
	
  if(!oSelect)return;
						
  // Now looop through all the list items entering all
  clearSelect(oSelect);
  for(var i=0;i<olist.length;i++) {
    elOption = new Option();
    // Now IE and NS have a different way to handle object creation.
    if(NS4) {
      elOption.value = olist.items[i].child
      elOption.text = olist.items[i].childcaption
      oSelect.options[idxSelect] = elOption
    } else if(IE4) {
      elOption.value = olist.items[i].child
      elOption.text = olist.items[i].childcaption
      oSelect.options.add(elOption,idxSelect)
    }
    idxSelect++;
    delete(elOption);
  }	
}

function UpdateSelect(szSelect,szForm,szParent,olist) {
  if(IE4)
    addOptions(document.all.item(szSelect),olist,szParent);
  else if(NS4)
    addOptions(eval('document.' + szForm + '.' + szSelect),olist,szParent);
}