var supported = (document.getElementById || document.all);
if (supported)
	{
	var max = 7;
	var shown = new Array();
	for (var i=1;i<=max;i++)
		{
		shown[i+1] = false;
		}
	}

function blocking(i)
	{
	if (!supported)
		{
		alert('This link does not work in your browser.');
		return;
		}
	shown[i] = (shown[i]) ? false : true;
	current = (shown[i]) ? 'block' : 'none';
	if (document.getElementById)
		{
		document.getElementById('number'+i).style.display = current;
		}
	else if (document.all)
		{
		document.all['number'+i].style.display = current;
		}
	
	if (document.getElementById('number'+i).style.display == "block") 
		{
		document.all['image'+i].src = "minus.gif";
		}
	else	{
		document.all['image'+i].src = "plus.gif";
		}
	}