function toggle( div_id )
{
	var el = document.getElementById( div_id );
	
	if( el.style.display == 'none' )
	{
		el.style.display = 'block';
	}
	else
	{
		el.style.display = 'none';
	}
}

function window_pos( popUpDivVar )
{
	if( typeof window.innerWidth != 'undefined' )
	{
		viewportwidth = window.innerHeight;
	}
	else
	{
		viewportwidth = document.documentElement.clientHeight;
	}
	
	if( ( viewportwidth > document.body.parentNode.scrollWidth ) && ( viewportwidth > document.body.parentNode.clientWidth ) )
	{
		window_width = viewportwidth;
	}
	else
	{
		if( document.body.parentNode.clientWidth > document.body.parentNode.scrollWidth )
		{
			window_width = document.body.parentNode.clientWidth;
		}
		else
		{
			window_width = document.body.parentNode.scrollWidth;
		}
	}
	
	var popUpDiv = document.getElementById( popUpDivVar );
	
	window_width		= window_width / 2 - 438; //438 is half popup's width
	popUpDiv.style.left	= window_width + 'px';
}

function popup( windowname )
{
	window_pos( windowname );
	toggle( windowname );		
}