var __content = document.getElementById("body");
var __skyscraper = document.getElementById("ad-skyscraper");
var __wrapper = document.getElementById("wrapper");
var __header = document.getElementById("header");


var skyTop;
var sidebarOffset;
var skyOffset;
var bottomLimit;

var BrowserDetect = {
    init: function () {
        this.browser = this.searchString(this.dataBrowser) || "An unknown browser";
        this.version = this.searchVersion(navigator.userAgent)
            || this.searchVersion(navigator.appVersion)
            || "an unknown version";
        this.OS = this.searchString(this.dataOS) || "an unknown OS";
    },
    searchString: function (data) {
        for (var i=0;i<data.length;i++) {
            var dataString = data[i].string;
            var dataProp = data[i].prop;
            this.versionSearchString = data[i].versionSearch || data[i].identity;
            if (dataString) {
                if (dataString.indexOf(data[i].subString) != -1)
                    return data[i].identity;
            }
            else if (dataProp)
                return data[i].identity;
        }
    },
    searchVersion: function (dataString) {
        var index = dataString.indexOf(this.versionSearchString);
        if (index == -1) return;
        return parseFloat(dataString.substring(index+this.versionSearchString.length+1));
    },
    dataBrowser: [
        {
            string: navigator.userAgent,
            subString: "Chrome",
            identity: "Chrome"
        },
        {   string: navigator.userAgent,
            subString: "OmniWeb",
            versionSearch: "OmniWeb/",
            identity: "OmniWeb"
        },
        {
            string: navigator.vendor,
            subString: "Apple",
            identity: "Safari",
            versionSearch: "Version"
        },
        {
            prop: window.opera,
            identity: "Opera"
        },
        {
            string: navigator.vendor,
            subString: "iCab",
            identity: "iCab"
        },
        {
            string: navigator.vendor,
            subString: "KDE",
            identity: "Konqueror"
        },
        {
            string: navigator.userAgent,
            subString: "Firefox",
            identity: "Firefox"
        },
        {
            string: navigator.vendor,
            subString: "Camino",
            identity: "Camino"
        },
        {       // for newer Netscapes (6+)
            string: navigator.userAgent,
            subString: "Netscape",
            identity: "Netscape"
        },
        {
            string: navigator.userAgent,
            subString: "MSIE",
            identity: "Explorer",
            versionSearch: "MSIE"
        },
        {
            string: navigator.userAgent,
            subString: "Gecko",
            identity: "Mozilla",
            versionSearch: "rv"
        },
        {       // for older Netscapes (4-)
            string: navigator.userAgent,
            subString: "Mozilla",
            identity: "Netscape",
            versionSearch: "Mozilla"
        }
    ],
    dataOS : [
        {
            string: navigator.platform,
            subString: "Win",
            identity: "Windows"
        },
        {
            string: navigator.platform,
            subString: "Mac",
            identity: "Mac"
        },
        {
               string: navigator.userAgent,
               subString: "iPhone",
               identity: "iPhone/iPod"
        },
        {
            string: navigator.platform,
            subString: "Linux",
            identity: "Linux"
        }
    ]

};
BrowserDetect.init();

function getY( oElement )
{
var iReturnValue = 0;
while( oElement != null ) {
iReturnValue += oElement.offsetTop;
oElement = oElement.offsetParent;
}
return iReturnValue;
}



function initStickyAd() {

    sidebarOffset = 10;
    skyOffset = getY(__skyscraper) - __wrapper.offsetTop;
    skyTop = skyOffset - sidebarOffset;
    bottomLimit = document.body.clientHeight - 810;


    var limit = __skyscraper.offsetHeight + skyOffset;

    var contentHeight = (window.innerHeight||document.documentElement.clientHeight||0);

    if (__content.offsetHeight > limit && contentHeight > 620) {
        __skyscraper.style.position = "absolute";
        __skyscraper.style.top = skyOffset+"px";
    }
    
    window.onscroll = stickAd;
}

function stickAd() {
    var pos = (window.pageYOffset||document.documentElement.scrollTop||document.body.scrollTop||0);

    if (pos > bottomLimit) {
        __skyscraper.style.top = bottomLimit - sidebarOffset;
    } else if (pos > skyTop + __wrapper.offsetTop) {
        var delta = pos - __wrapper.offsetTop + sidebarOffset;
        __skyscraper.style.top = delta+"px";
    } else {
        __skyscraper.style.top = skyOffset+"px";
    }
    


}

document.onload = initStickyAd();