$(function () {
    var screenwidth, screenheight, mytop, getPosLeft, getPosTop
    screenwidth = $(window).width();
    screenheight = $(window).height();
    //获取滚动条距顶部的偏移
    mytop = $(document).scrollTop();
    //计算弹出层的left
    getPosLeft = screenwidth / 2 - 200;
    //计算弹出层的top
    getPosTop = screenheight / 2 - 150;
    //css定位弹出层
    $("#divTypeManger").css({ "left": getPosLeft, "top": getPosTop });
    //当浏览器窗口大小改变时
    $(window).resize(function () {
        screenwidth = $(window).width();