var AtScroll = {
	objs: Array(),
	ids: {},
	isInit:false,
	init: function () {
		if (AtScroll.isInit==true)
			return ;
		var c = connect(window, 'onscroll', AtScroll.move);
		AtScroll.isInit = true;
	},
	add: function (id, top) {
		var o = $(id);
		if (o==null) {
			return ;
		}
		if (typeof(top)=='undefined') {
			top = 0;
		}
		AtScroll.objs[AtScroll.objs.length] = o;
		var pos = getElementPosition(o);
		AtScroll.ids[id] = { };
		AtScroll.ids[id]['top'] = top;
		AtScroll.ids[id]['left'] = pos.x;
		var scrollTop = (document.body.scrollTop) ? document.body.scrollTop : document.documentElement.scrollTop;
		if (scrollTop>top)
			AtScroll.move(null);
	},
	move: function (e) {
		var scrollTop = (document.body.scrollTop) ? document.body.scrollTop : document.documentElement.scrollTop;
		for (var i=0; i<AtScroll.objs.length; i++) {
			// var pos = getElementPosition(AtScroll.objs[i]);
			var top = AtScroll.ids[AtScroll.objs[i].id]['top'];
			var left = AtScroll.ids[AtScroll.objs[i].id]['left'];

			if (top>0 && top == scrollTop) 
				;
			else if (top>0 && top > scrollTop) 
				Move(AtScroll.objs[i], {'x':left, 'y':top, 'mode':'absolute'});
			else 
				Move(AtScroll.objs[i], {'x':left, 'y':scrollTop+10, 'mode':'absolute'});
		}
	}
};