function cache()
{
	var elems = document.getElementsByTagName("div");
	for (i=0; i<elems.length; i++) 
	{
		for(j=1;j<=8;j++)
		{
			var classSession = "session"+j;
			if (elems[i].className.indexOf(classSession) != -1)
			{
				elems[i].style.display="none";
			}
		}
	}
}
	
function openDesc(ref)
{
	var elems = document.getElementsByTagName("div");
	for (i=0; i<elems.length; i++) 
	{
		if (elems[i].className.indexOf(ref) != -1 && elems[i].style.display=="none")
		{
			elems[i].style.display="";
		}
	}
}
function closeDesc(ref)
{
	var elems = document.getElementsByTagName("div");
	for (i=0; i<elems.length; i++) 
	{
		if (elems[i].className.indexOf(ref) != -1 && elems[i].style.display=="")
		{
			elems[i].style.display="none";
		}
	}
}