//detect browser
var nn4 = (document.layers)? true:false;
var ie4 = (document.all)? true:false;
var dom = (document.getElementById)? true:false;

//Create a new layer object
function layerObj(id){
if(nn4){
this.id  = document.layers[id];
this.css = this.id;
} else if(ie4){
this.id  = document.all[id];
this.css = this.id.style;
} else if (dom){
this.id  = document.getElementById(id);
this.css = this.id.style;
}
//object method references
this.show = objShow;
this.hide = objHide;

}

//hide layer
function objHide(){
this.css.visibility = "hidden";
//menucorbut.src='gif/corbut.gif';
}

//show layer
function objShow(){
this.css.visibility = "visible";
//menucorbut.src='gif/corbutac.gif'; 
}

/****************************************************/

var elm = null;
//change font color & background color in dropdown menu in ie4, ie5 & nn6
function doOver(id){
if(ie4){
document.all['t'+id].style.backgroundColor='#EEEEEE';
document.all['a'+id].style.color='#000000';
elm = id;
}
else if(dom){
document.getElementById('t'+id).style.backgroundColor='#EEEEEE';
document.getElementById('a'+id).style.color='#000000';
elm = id;
}
}
//change font color & background color in dropdown menu in ie4, ie5 & nn6