function closePopup() {
	$('.popup').hide();
	$('.blind').remove();
}
function setCenter(item) {
	windowHeight = document.documentElement.clientHeight;
	currentOffset = document.documentElement.scrollTop || document.body.scrollTop;
	currentOffset = currentOffset + parseInt((windowHeight - $(item).height()) / 2);
	pLeft = (document.body.clientWidth - $(item).width()) / 2;
	$(item).css({top:currentOffset,left:pLeft}).show();
}
function showPopup(popup) {
	blind = $('<div class="blind"></div>');
	pageHeight = (document.documentElement.offsetHeight > document.body.clientHeight) ? document.documentElement.offsetHeight : document.body.clientHeight;
	blind.height(pageHeight).click(function(){
		closePopup();
		return false;
	}).appendTo('body');
	popup = $('#'+popup);
	setCenter(popup);
	popup.show();
}