/*===================================================================
 Author: Matt Kruse
 
 View documentation, examples, and source code at:
     http://www.JavascriptToolbox.com/

 NOTICE: You may use this code for any purpose, commercial or
 private, without any further permission from the author. You may
 remove this notice from your final code if you wish, however it is
 appreciated by the author if at least the web site address is kept.

 This code may NOT be distributed for download from script sites, 
 open source CDs or sites, or any other distribution method. If you
 wish you share this code with others, please direct them to the 
 web site above.
 
 Pleae do not link directly to the .js files on the server above. Copy
 the files to your own server for use with your site or webapp.
 ===================================================================*/
var ObjectPosition = (function() {
	// Resolve a string identifier to an object
	// ========================================
	function resolveObject(s) {
		if (document.getElementById && document.getElementById(s)!=null) {
			return document.getElementById(s);
		}
		else if (document.all && document.all[s]!=null) {
			return document.all[s];
		}
		else if (document.anchors && document.anchors.length && document.anchors.length>0 && document.anchors[0].x) {
			for (var i=0; i<document.anchors.length; i++) {
				if (document.anchors[i].name==s) { 
					return document.anchors[i]
				}
			}
		}
	}
	
	var pos = {};
	pos.$VERSION = 1.0;
	
	// Set the position of an object
	// =============================
	pos.set = function(o,left,top) {
		if (typeof(o)=="string") {
			o = resolveObject(o);
		}
		if (o==null || !o.style) {
			return false;
		}
		
		// If the second parameter is an object, it is assumed to be the result of getPosition()
		if (typeof(left)=="object") {
			var pos = left;
			left = pos.left;
			top = pos.top;
		}
		
		o.style.left = left + "px";
		o.style.top = top + "px";
		return true;
	};
	
	// Retrieve the position and size of an object
	// ===========================================
	pos.get = function(o) {
		var fixBrowserQuirks = true;
			// If a string is passed in instead of an object ref, resolve it
		if (typeof(o)=="string") {
			o = resolveObject(o);
		}
		
		if (o==null) {
			return null;
		}
		
		var left = 0;
		var top = 0;
		var width = 0;
		var height = 0;
		var parentNode = null;
		var offsetParent = null;
	
		
		offsetParent = o.offsetParent;
		var originalObject = o;
		var el = o; // "el" will be nodes as we walk up, "o" will be saved for offsetParent references
		while (el.parentNode!=null) {
			el = el.parentNode;
			if (el.offsetParent==null) {
			}
			else {
				var considerScroll = true;
				/*
				In Opera, if parentNode of the first object is scrollable, then offsetLeft/offsetTop already 
				take its scroll position into account. If elements further up the chain are scrollable, their 
				scroll offsets still need to be added in. And for some reason, TR nodes have a scrolltop value
				which must be ignored.
				*/
				if (fixBrowserQuirks && window.opera) {
					if (el==originalObject.parentNode || el.nodeName=="TR") {
						considerScroll = false;
					}
				}
				if (considerScroll) {
					if (el.scrollTop && el.scrollTop>0) {
						top -= el.scrollTop;
					}
					if (el.scrollLeft && el.scrollLeft>0) {
						left -= el.scrollLeft;
					}
				}
			}
			// If this node is also the offsetParent, add on the offsets and reset to the new offsetParent
			if (el == offsetParent) {
				left += o.offsetLeft;
				if (el.clientLeft && el.nodeName!="TABLE") { 
					left += el.clientLeft;
				}
				top += o.offsetTop;
				if (el.clientTop && el.nodeName!="TABLE") {
					top += el.clientTop;
				}
				o = el;
				if (o.offsetParent==null) {
					if (o.offsetLeft) {
						left += o.offsetLeft;
					}
					if (o.offsetTop) {
						top += o.offsetTop;
					}
				}
				offsetParent = o.offsetParent;
			}
		}
		
	
		if (originalObject.offsetWidth) {
			width = originalObject.offsetWidth;
		}
		if (originalObject.offsetHeight) {
			height = originalObject.offsetHeight;
		}
		
		return {'left':left, 'top':top, 'width':width, 'height':height
				};
	};
	
	// Retrieve the position of an object's center point
	// =================================================
	pos.getCenter = function(o) {
		var c = this.get(o);
		if (c==null) { return null; }
		c.left = c.left + (c.width/2);
		c.top = c.top + (c.height/2);
		return c;
	};
	
	return pos;
})();