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 agregaOpcion(oSelect,nIndice,cClave,cDescri){
elSelectOption = new Option();
elSelectOption.value = cClave;
elSelectOption.text = cDescri;
if(NS4) oSelect.options[nIndice] = elSelectOption;
else if(IE4) oSelect.options.add(elSelectOption,nIndice);
delete(elSelectOption);
}

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){
if(idxSelect==0){
agregaOpcion(oSelect,0,"0","ALL");
idxSelect++;
} 
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);
} 
}

if(oSelect.length<=0){
agregaOpcion(oSelect,0,"0","ALL");
}
oSelect.selectedIndex = 0; 
}

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);
}