var openImg = new Image();
openImg.src = "/image/plus.gif";
var closedImg = new Image();
closedImg.src = "/image/minus.gif";
function showBranch(chapter){
	var objBranch = document.getElementById(chapter).style;
	if(objBranch.display=="block")
		objBranch.display="none";
	else
		objBranch.display="block";
	swapFolder('I'+chapter);
}
function showBranch1(article){
	var objBranch = document.getElementById('P'+article).style;
	if(objBranch.display=="block")
		objBranch.display="none";
	else
		objBranch.display="block";
	swapFolder('Po'+article);		
}

function swapFolder(img){
	objImg = document.getElementById(img);
	if(objImg.src.indexOf('/image/minus.gif')>-1)
		objImg.src = openImg.src;
	else
		objImg.src = closedImg.src;
}