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 blanket_size(popUpDivVar)
{
	if (typeof window.innerWidth != 'undefined')
	{
		viewportheight = window.innerHeight;
	}
	else
	{
		viewportheight = document.documentElement.clientHeight;
	}
	if ((viewportheight > document.body.parentNode.scrollHeight) && (viewportheight > document.body.parentNode.clientHeight))
	{
		blanket_height = viewportheight;
	}
	else
	{
		if (document.body.parentNode.clientHeight > document.body.parentNode.scrollHeight)
		{
			blanket_height = document.body.parentNode.clientHeight;
		}
		else
		{
			blanket_height = document.body.parentNode.scrollHeight;
		}
	}

	var blanket = document.getElementById('blanket');
	blanket.style.height = blanket_height + 'px';
	var popUpDiv = document.getElementById(popUpDivVar);
	popUpDiv_height=blanket_height/2-150;//150 is half popup's height
	popUpDiv.style.top = popUpDiv_height + 'px';
}

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/2-150;//150 is half popup's width
	popUpDiv.style.left = window_width + 'px';
}

function popup(windowname)
{
	blanket_size(windowname);
	window_pos(windowname);
	toggle('blanket');
	toggle(windowname);		
}