function toggle(div_id)

{

	var el = document.getElementById(div_id);

	if ( el.style.display == 'none' ) {	el.style.display = 'block';}

	else {el.style.display = 'none';}

}

var popupOn = false;

function popupPosition(windowname, contantId)

{

	if (!popupOn) {

		return;

	}

	var blanket_height = $("#" + contantId).height();

	var window_width = $("#" + contantId).width();

	var blanket = $("#blanket");

	var popup = $("#"+windowname);

	var popupHeight = popup.height();

	var popupTop = (blanket_height - popupHeight) / 2;

	popup.css({"top" : + popupTop +'px'});

	var popupWidth = popup.width();

	var popupLeft = (window_width - popupWidth) / 2;

	popup.css({"left" : + popupLeft +'px'});	

}

function popup(windowname, contantId)

{

	popupOn = !popupOn;

	popupPosition(windowname, contantId);

	toggle('blanket');

	toggle(windowname);

}