function centerDiv(div){
  	var DIVwidth = $(div).width();	
	var DIVheight = $(div).height();
	var SCREENwidth = $(document).width();
	var SCREENheight = $(window).height();	
	var SCREENscrolltop = $(window).scrollTop();
    $(div).hide();
	$(div).css({"position":"absolute","left":(SCREENwidth-DIVwidth)/2+"px","top":(SCREENheight-DIVheight)/2+SCREENscrolltop+"px"});
	$(div).show();

}

var div = "#box_logo_home";

$(document).ready(function(){
	centerDiv(div);
	centerDiv('#cont_banner');
});

$(window).scroll(function(){
	centerDiv(div);
	centerDiv('#cont_banner');
});

$(window).resize(function(){
	centerDiv(div);
	centerDiv('#cont_banner');
});