让弹出层在屏幕上居中显示

html:

<div class="submitsuccess">提交成功</div>

css:

.submitsuccess{background: rgba(0,0,0,0.5); 150px;position: absolute;margin-left:-75px;top:50%;left:50%; height: 50px;text-align: center;line-height: 50px;color: #fff;font-size: 18px;border-radius: 5px;display:none;z-index:999;}

js:

var top=($(window).height()-$(".").height())/2;//让其弹出层在中间显示
var left=($(window).width()-$(".submitsuccess").width())/2;//让其弹出层在中间显示
var scrollTop=$(document).scrollTop();
var scrollLeft=$(document).scrollLeft();
$(".submitsuccess").css({position:'absolute', 'top':top + scrollTsubmitsuccessop, 'left':left + scrollLeft}).stop().fadeIn(1000)//弹出层显示
$('.submitsuccess').fadeOut(1000);