function __getIEVersion() {  
        var rv = -1; // Return value assumes failure.  
        if (navigator.appName == 'Microsoft Internet Explorer') {  
            var ua = navigator.userAgent;  
            var re = new RegExp("MSIE ([0-9]{1,}[\.0-9]{0,})");  
            if (re.exec(ua) != null)  
                rv = parseFloat(RegExp.$1);  
        }  
        return rv;  
    }  
      
    function __getOperaVersion() {  
        var rv = 0; // Default value  
        if (window.opera) {  
            var sver = window.opera.version();  
            rv = parseFloat(sver);  
        }  
        return rv;  
    }  
      
    var __userAgent = navigator.userAgent;  
    var __isIE =  navigator.appVersion.match(/MSIE/) != null;  
    var __IEVersion = __getIEVersion();  
    var __isIENew = __isIE && __IEVersion >= 8;  
    var __isIEOld = __isIE && !__isIENew;  
      
    var __isFireFox = __userAgent.match(/firefox/i) != null;  
    var __isFireFoxOld = __isFireFox && ((__userAgent.match(/firefox\/2./i) != null) || (__userAgent.match(/firefox\/1./i) != null));  
    var __isFireFoxNew = __isFireFox && !__isFireFoxOld;  
      
    var __isWebKit =  navigator.appVersion.match(/WebKit/) != null;  
    var __isChrome =  navigator.appVersion.match(/Chrome/) != null;  
    var __isOpera =  window.opera != null;  
    var __operaVersion = __getOperaVersion();  
    var __isOperaOld = __isOpera && (__operaVersion < 10);  
      
    function __parseBorderWidth(width) {  
        var res = 0;  
        if (typeof(width) == "string" && width != null && width != "" ) {  
            var p = width.indexOf("px");  
            if (p >= 0) {  
                res = parseInt(width.substring(0, p));  
            }  
            else {  
                //do not know how to calculate other values (such as 0.5em or 0.1cm) correctly now  
                //so just set the width to 1 pixel  
                res = 1;   
            }  
        }  
        return res;  
    }  
      
      
    //returns border width for some element  
    function __getBorderWidth(element) {  
        var res = new Object();  
        res.left = 0; res.top = 0; res.right = 0; res.bottom = 0;  
        if (window.getComputedStyle) {  
            //for Firefox  
            var elStyle = window.getComputedStyle(element, null);  
            res.left = parseInt(elStyle.borderLeftWidth.slice(0, -2));    
            res.top = parseInt(elStyle.borderTopWidth.slice(0, -2));    
            res.right = parseInt(elStyle.borderRightWidth.slice(0, -2));    
            res.bottom = parseInt(elStyle.borderBottomWidth.slice(0, -2));    
        }  
        else {  
            //for other browsers  
            res.left = __parseBorderWidth(element.style.borderLeftWidth);  
            res.top = __parseBorderWidth(element.style.borderTopWidth);  
            res.right = __parseBorderWidth(element.style.borderRightWidth);  
            res.bottom = __parseBorderWidth(element.style.borderBottomWidth);  
        }  
         
        return res;  
    }  
      
      
    //returns the absolute position of some element within document  
    function getElementAbsolutePos(elemID) {  
        var element;  
        if (typeof(elemID) == "string") {  
            element = document.getElementById(elemID);  
        }  
        else {  
            element = elemID;  
        }  
      
        var res = new Object();  
        res.x = 0; res.y = 0;  
        if (element !== null) {  
            res.x = element.offsetLeft;  
      
            var offsetParent = element.offsetParent;  
            var offsetParentTagName = offsetParent != null ? offsetParent.tagName.toLowerCase() : "";  
      
            if (__isIENew  && offsetParentTagName == 'td') {  
                res.y = element.scrollTop;  
            }  
            else {  
                res.y = element.offsetTop;  
            }  
              
            var parentNode = element.parentNode;  
            var borderWidth = null;  
      
            while (offsetParent != null) {  
                res.x += offsetParent.offsetLeft;  
                res.y += offsetParent.offsetTop;  
                  
                var parentTagName = offsetParent.tagName.toLowerCase();   
      
                if ((__isIEOld && parentTagName != "table") || (__isFireFoxNew && parentTagName == "td")  || __isChrome) {            
                    borderWidth = __getBorderWidth(offsetParent);  
                    res.x += borderWidth.left;  
                    res.y += borderWidth.top;  
                }  
                  
                if (offsetParent != document.body && offsetParent != document.documentElement) {  
                    res.x -= offsetParent.scrollLeft;  
                    res.y -= offsetParent.scrollTop;  
                }  
      
      
                //next lines are necessary to fix the problem with offsetParent  
                if (!__isIE && !__isOperaOld || __isIENew) {  
                    while (offsetParent != parentNode && parentNode !== null) {  
                        res.x -= parentNode.scrollLeft;  
                        res.y -= parentNode.scrollTop;  
                        if (__isFireFoxOld || __isWebKit) {  
                            borderWidth = __getBorderWidth(parentNode);  
                            res.x += borderWidth.left;  
                            res.y += borderWidth.top;  
                        }  
                        parentNode = parentNode.parentNode;  
                    }      
                }  
      
                parentNode = offsetParent.parentNode;  
                offsetParent = offsetParent.offsetParent;  
            }  
        }  
        return res;  
    }