A jQuery script for vertical centering

vCenter.js

function vcenter(a, b) {
	var wHeight = $(window).height();
	var fHeight = $(a).height();
	var nHeight = (wHeight / 2) - (fHeight);
	if (!b || b == "" || b == null) {
		var b = a;
	}
	$(b).css({
		'position' : 'relative',
		'top' : nHeight
	});	
}

$(window).ready( function () { 
		vcenter('#main'); 
	}).resize( function () { 
		vcenter('#main'); 
});