div在页面居中显示

$(window).resize(function(){ 
$('.className').css({ 
position:'absolute', 
left: ($(window).width() - $('.className').outerWidth())/2, 
top: ($(window).height() - $('.className').outerHeight())/2 + $(document).scrollTop() 
}); 
}); 
//初始化函数 
$(window).resize();