window.onload = init;
var clicked = false;
var d = document;

function init() {
	if(!d.getElementById)return;
	ulObj = d.getElementById("tree");
	liObj = ulObj.getElementsByTagName("li");
	i=0;
	while(liObj[i]) {
		if(liObj[i].childNodes.length) {
			j=0;
			while(liObj[i].childNodes[j]) { 
				if(liObj[i].childNodes[j].nodeType == 1) {
					liObj[i].style.listStyleType = "disc";
					liObj[i].childNodes[j].style.display = "none";
					//liObj[i].setAttribute("tabindex","-1");
					liObj[i].onmousedown = function() { exposeChildren(this); clicked = true; }
					liObj[i].onmouseup = function() { clicked = false; }
					//liObj.onfocus = liObj[i].onmousedown;
					//liObj.onblur = liObj[i].onmouseup;
				}
				j++;
			}
		}
		i++;
	}
}

function exposeChildren(obj) {
	i=0;
	if(clicked)return;
	while(obj.childNodes[i]) {
		if(obj.childNodes[i].nodeType == 1) {
			if(obj.childNodes[i].style.display == "none") {
				obj.childNodes[i].style.display = "block";
			} else {
				obj.childNodes[i].style.display = "none";
			}
		}
		i++;
	}
}