用css或jquery方式 使div 水平、竖直均居中

?

.className{width:270px;height:150px;position:absolute;left:50%;top:50%;margin:-75px 0 0 -135px;}

?

jquery方法$(document).ready(function(){    $(window).resize(function(){  $('.className').css({   position:'absolute',   left: ($(window).width()      - $('.className').outerWidth())/2,   top: ($(window).height()      - $('.className').outerHeight())/2  }); });  // To initially run the function: $(window).resize();});

?