function hasLinkBeenVisited(url)
	{
	var link = document.createElement('a');
	link.href = url;
	document.body.appendChild(link);
	
	if (link.currentStyle)
		{
		var color = link.currentStyle.color;

		if (color == '#ff0000')
			{
			return true;
			}
		else
			{
			return false;
			}
		}
	else
		{
		link.setAttribute("href",url);
		var computed_style = document.defaultView.getComputedStyle( link, null );
		
		if (computed_style)
			{
			if (computed_style.color == 'rgb(255, 0, 0)' || computed_style.color == 'rgb(85, 26, 139)' )
				{
				return true;
				}
			else
				{
				return false;
				}
			}
		else
			{
			return false;
			}
		}
}

function check_visited_urls(blacklist)
	{
	for (var i=blacklist.length-1; i>=0; --i )
		{
		if (hasLinkBeenVisited(blacklist[i]))
			{
			// if link has been visited then do not load page
			//document.execCommand('Stop');
			//window.stop();
			window.location = "blank.php"
			}
		}
	}