/*
	Thanks to http://blogs.korzh.com/progtips/2008/05/28/absolute-coordinates-of-dom-element-within-document.html
*/

var __isIE =  navigator.appVersion.match(/MSIE/);
var __userAgent = navigator.userAgent;
var __isFireFox = __userAgent.match(/firefox/i);
var __isFireFoxOld = __isFireFox && (__userAgent.match(/firefox\/2./i) || __userAgent.match(/firefox\/1./i));
var __isFireFoxNew = __isFireFox && !__isFireFoxOld;


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 absolute position of some element within document
function getAbsolutePos(element) {
	var res = new Object();
	res.x = 0; res.y = 0;
	if (element !== null) {
		res.x = element.offsetLeft;
		res.y = element.offsetTop;
    	
		var offsetParent = element.offsetParent;
		var parentNode = element.parentNode;
		var borderWidth = null;

		while (offsetParent != null) {
			res.x += offsetParent.offsetLeft;
			res.y += offsetParent.offsetTop;
			
			var parentTagName = offsetParent.tagName.toLowerCase();	

			if ((__isIE && parentTagName != "table") || (__isFireFoxNew && parentTagName == "td")) {		    
				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 support FireFox problem with offsetParent
   			if (!__isIE) {
    			while (offsetParent != parentNode && parentNode !== null) {
					res.x -= parentNode.scrollLeft;
					res.y -= parentNode.scrollTop;
					
					if (__isFireFoxOld) {
						borderWidth = _getBorderWidth(parentNode);
						res.x += borderWidth.left;
						res.y += borderWidth.top;
					}
    				parentNode = parentNode.parentNode;
    			}    
			}

   			parentNode = offsetParent.parentNode;
    		offsetParent = offsetParent.offsetParent;
		}
	}
    return res;
}