var quantity=1;

function getElement(id) {
  if (document.getElementById) {
  	return document.getElementById(id);
  } else if (document.all) {
		return document.all[id];
  } else if (document.layers) {
   	return document.layers[id];
  }
}

function add_total(price) {
	elem=document.getElementById('price');
	
	currentPrice=parseInt(elem.innerHTML);
	currentPrice+=price;
	
	elem.innerHTML=currentPrice;
}

function subtract_total(price) {
	elem=document.getElementById('price');
	
	currentPrice=parseInt(elem.innerHTML);
	currentPrice-=price;
	
	elem.innerHTML=currentPrice;
}

function change_quantity(quantity_local, product_price) {
	if (quantity_local) {
		elem=document.getElementById('price');
		
		currentPrice=parseInt(elem.innerHTML);
		currentPrice-=quantity*product_price;
		currentPrice+=quantity_local*product_price;
		
		elem.innerHTML=currentPrice;
		quantity=quantity_local;
	}
}

function open_message(content) {
    Shadowbox.open({
        player:     'html',
        content:    '<div class="details">'+content+'</div>'
    });
}

function changeDisplay(id) {
	var element=getElement(id);
	
	if (element.style.display=='none')
		element.style.display='block';
	else
		element.style.display='none';
}