$(document).ready(function(){
	$(window).resize(function(){
		$('#wrapper').css({
			position: 'absolute',
			left: ($(window).width() - $('#wrapper').outerWidth())/2,
			top: ($(window).height() - $('#wrapper').outerHeight())/2
		});
	});
	// TO INITIALLY RUN THE FUNCTION:
	$(window).resize();
});