var currentServletName = 'foo';
  
  /* Add To Cart */
  function addToCart(servletName, invId)
  {
    currentServletName = servletName;
    cartUrl = './' + servletName + '/addtocart?invId=' + invId;
    new Ajax.Updater('cartMessage', cartUrl, {onComplete: getCartQuantity});
  }
  
  /* Get Cart Quantity */
  function getCartQuantity(request)
  {
    totalUrl = './'+currentServletName+'/addtocart';
    new Ajax.Updater('cartTotal', totalUrl);
  }