Jquey 弹出层

jQuery.fn.extend(
{
    OpenDiv: function () {
        var sWidth, sHeight;
        sWidth = window.screen.availWidth;
        if (window.screen.availHeight > document.body.scrollHeight) {
            sHeight = window.screen.availHeight;
        } else {
            sHeight = document.body.scrollHeight + 20;
        }
        var maskObj = document.createElement("div");
        maskObj.setAttribute('id', 'BigDiv');
        maskObj.style.position = "absolute";
        maskObj.style.top = "0";
        maskObj.style.left = "0";
        maskObj.style.background = "#111";
        maskObj.style.filter = "Alpha(opacity=70);";
        maskObj.style.opacity = "0.7";
        maskObj.style.width = sWidth + "px";
        maskObj.style.height = sHeight + "px";
        maskObj.style.zIndex = "10000";
        $("body").attr("scroll", "no");
        document.body.appendChild(maskObj);
        $("#BigDiv").data("divbox_selectlist", $("select:visible"));
        $("select:visible").hide();
        $("#BigDiv").attr("divbox_scrolltop", $.ScrollPosition().Top);
        $("#BigDiv").attr("divbox_scrollleft", $.ScrollPosition().Left);
        $("#BigDiv").attr("htmloverflow", $("html").css("overflow"));
        $("html").css("overflow", "hidden");
        window.scrollTo($("#BigDiv").attr("divbox_scrollleft"), $("#BigDiv").attr("divbox_scrolltop"));
        var MyDiv_w = this.width();
        var MyDiv_h = this.height();
        MyDiv_w = parseInt(MyDiv_w);
        MyDiv_h = parseInt(MyDiv_h);
        var width = $.PageSize().Width;
        var height = $.PageSize().Height;
        var left = $.ScrollPosition().Left;
        var top = $.ScrollPosition().Top;
        var Div_topposition = top + (height / 2) - (MyDiv_h / 2);
        var Div_leftposition = left + (width / 2) - (MyDiv_w / 2);
        this.css("position", "absolute");
        this.css("z-index", "10001");
        this.css("left", Div_leftposition + "px");
        this.css("top", Div_topposition + "px");
        if ($.browser.mozilla) {
            this.show();
            return;
        }
        this.fadeIn("fast");
    }
, CloseDiv: function () {
    if ($.browser.mozilla) {
        this.hide();
    } else {
        this.fadeOut("fast");
    } $("html").css("overflow", $("#BigDiv").attr("htmloverflow"));
    window.scrollTo($("#BigDiv").attr("divbox_scrollleft"), $("#BigDiv").attr("divbox_scrolltop"));
    $("#BigDiv").data("divbox_selectlist").show();
    $("#BigDiv").remove();
}
});
$.extend(
{
    PageSize: function () {
        var width = 0;
        var height = 0;
        width = window.innerWidth != null ? window.innerWidth : document.documentElement && document.documentElement.clientWidth ? document.documentElement.clientWidth : document.body != null ? document.body.clientWidth : null;
        height = window.innerHeight != null ? window.innerHeight : document.documentElement && document.documentElement.clientHeight ? document.documentElement.clientHeight : document.body != null ? document.body.clientHeight : null;
        return { Width: width, Height: height };
    }
, ScrollPosition: function () {
    var top = 0, left = 0;
    if ($.browser.mozilla) {
        top = window.pageYOffset;
        left = window.pageXOffset;
    }
    else if ($.browser.msie) {
        top = document.documentElement.scrollTop;
        left = document.documentElement.scrollLeft;
    }
    else if (document.body) {
        top = document.body.scrollTop;
        left = document.body.scrollLeft;
    }
    return { Top: top, Left: left };
}
});

Css样式：

#divSCA
{
position: absolute;
600px;
height: 300px;
font-size: 12px; 
border: 0px solid #000;
z-index: 10001;
display: none;
background-color:#eee;
}
#Close_Button
{
 clear:both;
 float:right;
 margin-right:2px;
 margin-top:5px;
}
#div_Inner
{
 clear:both;
 580px;
 height:260px;
 margin-top:20px;
 background-color:White;
}