Jquery 实现弹出层插件

                $(tag).css({
                    ‘left’: ev.pageX – x + $(tag).width() / 2, //本人的布局需要加这个
                    ‘top’: ev.pageY – y + $(tag).height() / 2
                });
            });
        });
        $(document).mouseup(function () {
            $(this).unbind(“mousemove”);
        });
    }

6：样式表

　　弹出层的布局使用的是top和left+margin-top负值，所以我的js里面有多加高度和宽度的一半

.mask
{
    position: fixed;
    width: 100%;
    height: 100%;
    background-color: white;
    overflow: scroll;
    filter: alpha(opacity=50);
    -moz-opacity: 0.5;
    opacity: 0.5;
    z-index: 20;
    overflow: auto;
    top: 0px;
    right: 0px;
}
.PopUp
{
    padding: 0px;
    position: absolute;
    z-index: 21 !important;
    background-color: White;
    border-style: solid solid solid solid;
    border-width: 1px;
    border-color: #C0C0C0;
    left: 50%;
    top: 50%;
}
.PopHead
{
    background-color: #F0F0F0;
    border-bottom-style: solid;
    border-bottom-width: 1px;
    border-bottom-color: #C0C0C0;
    height: 30px;
    cursor: move;
    clip: rect(0px, auto, auto, 0px);
}
.PopHead b
{
    float: left;
    display: block;
    color: #C0C0C0;
    font-family: System;
    font-size: medium;
    line-height: 30px;
    text-indent: 2em;
}
.PopHead span
{
    float: right;
    display: block;
    text-align: right;
    line-height: 30px;
    cursor: pointer;
    text-indent: 5px;