function IsNumeric(strString)
   //  check for valid numeric strings	
   {
   var strValidChars = "0123456789.-";
   var strChar;
   var blnResult = true;

   if (strString.length == 0) return false;

   //  test strString consists of valid characters listed above
   for (i = 0; i < strString.length && blnResult == true; i++)
      {
      strChar = strString.charAt(i);
      if (strValidChars.indexOf(strChar) == -1)
         {
         blnResult = false;
         }
      }
   return blnResult;
}


// shoping cart
function add_to_cart(id, elem, quantity) {
	if (IsNumeric(quantity)) {
	//elem.firstChild.title = "This product is in your cart";
	//elem.firstChild.alt = "This product is in your cart";
	//elem.firstChild.src = '/images/bought.gif';
	new Ajax.Request('/cart/add_to_cart/'+id+'/'+quantity+'/', {method: "GET", onSuccess: addedToCart});
	dispCart();
	} else {
		alert ('No quantity!');
	}
}

function remove_from_cart(id, elem) {
	elem.parentNode.parentNode.style.display = "none";
	new Ajax.Request('/cart/remove_from_cart/'+id, {method: "GET", onSuccess: addedToCart});
	dispCart();
	refreshTotal();
}

var addedToCart = function (t) {
	displayMessage(t.responseText);
}

function dispCart() {
	$('shopping_cart').innerHTML = '<img src="/images/preloader.gif" width="16" height="16" />';
	var url = "/cart/shopping_cart/";
	new Ajax.Request(url, {onSuccess: doRefreshCart});
}
var doRefreshCart = function (t) {
	$('shopping_cart').innerHTML = t.responseText;
}

function refreshTotal() {
	var url = "/cart/get_total/";
	new Ajax.Request(url, {onSuccess: doRefreshTotal});
}
var doRefreshTotal = function (t) {
	$('total').innerHTML = t.responseText;
}