var DHTML = (document.getElementById || document.all || document.layers);
function getObj(name)
{
  if (document.getElementById)
  {
  	this.obj = document.getElementById(name);
	this.style = document.getElementById(name).style;
  }
  else if (document.all)
  {
	this.obj = document.all[name];
	this.style = document.all[name].style;
  }
  else if (document.layers)
  {
   	this.obj = document.layers[name];
   	this.style = document.layers[name];
  }
}

function invi(who,target)
{
	if (!DHTML) return;
	var x = new getObj(target);
	var whoElem = new getObj(who);
	if(x.style.display == 'none'){
		x.style.display = 'block';
		whoElem.obj.className = 'tree_open';
	}else{
		x.style.display = 'none';
		whoElem.obj.className = 'tree';
	}
}