function collapse_folder(id)
{	
	element = $(id);
  element.style.height = "15px";          
  element.style.overflow = "hidden";
  element.innerHTML = '<a onclick="expand_folder(\'' + element.id + '\')"><img border="0" src="img/icons/plus.png"></a> <img src="img/icons/folder.gif' + element.innerHTML.substring(element.innerHTML.indexOf('.gif') + 4, element.innerHTML.length);
}

function expand_folder(id)
{
	element = $(id);	
	element.innerHTML = '<a onclick="collapse_folder(\'' + element.id + '\')"><img border="0" src="img/icons/minus.png"></a> <img src="img/icons/folderopen.gif' + element.innerHTML.substring(element.innerHTML.indexOf('.gif') + 4, element.innerHTML.length); 
	element.style.height = '';
}

var LastMarked = -1;

function mark_folder(id)
{
	if(LastMarked > -1)
	{
		name = 'file_' + LastMarked
		element = $(name)
		element.style.fontWeight = "normal";
	}
	LastMarked = id;
	name = 'file_' + id;
	element = $(name);
	element.style.fontWeight = "bold";
}