gistfile1.js

(function(){
    var styleString = Element.getComputedStyle;
    function styleNumber(element, style){
    	return styleString(element, style).toInt() || 0;
    };
    function isBody(element){
    	return (/^(?:body|html)$/i).test(element.tagName);
    };
    Element.implement({
    	getPosition: function(relative){
    		if (isBody(this)) return {x: 0, y: 0};
    		var offset = this.getOffsets(), scroll = this.getScrolls();
    		var position = {x: offset.x - scroll.x, y: offset.y - scroll.y};
    		var relativePosition = (relative && (relative = document.id(relative))) ? relative.getPosition() : {x: 0, y: 0};
    		if(relative){
    		    relativePosition.x += relative.getStyle('border-left-width').toInt();
    		    relativePosition.y += relative.getStyle('border-top-width').toInt();
    		}
    		return {x: position.x - relativePosition.x, y: position.y - relativePosition.y};
    	}
    });
})();