new Draggable('blue_box', {
	revert: true
});
new Draggable('green_box', {
	revert: true
});
Droppables.add('shopping_cart', {
	onDrop: addItem,
	hoverclass: 'hover'
});
function addItem(dragged, dropped, event){
	var itemCount = $('items_in_cart').select('li[id="item' + dragged.id + '"] span').first();
	if(itemCount == undefined){
		$('items_in_cart').insert({
			bottom: '<li id="item' + dragged.id + '"><span>1</span>x ' + dragged.title + '</li>'
		});
	} else {
		itemCount.update(parseInt(itemCount.innerHTML) + 1);
	}	
}

$$('head').first().insert({
    bottom: new Element('style', {
        type: 'text/css'
    }).update('div#shopping_cart.hover { border: 5px dashed #aaa !important; }')
});