function something()
{
	var x = window.localStorage.getItem('bbb');
	x = x*1 + 1;
	window.localStorage.setItem('bbb', x);
	alert(x);
};



function add_to_cart(id)
{
  var key = 'product_' + id
var x = window.localStorage.getItem(key);
x = x*1 + 1;
window.localStorage.setItem(key, x);
}
function something()
{
	var x = window.localStorage.getItem('bbb');
	x = x*1 + 1;
	window.localStorage.setItem('bbb', x);
	alert(x);
};



function add_to_cart(id)
{
var key = 'product_' + id 

var x = window.localStorage.getItem(key);
x = x*1 + 1;
window.localStorage.setItem(key, x);
//number of items in the cart
alert('Items in your cart: ' +cart_get_number_of_items());
};

function cart_get_number_of_items()
{

  var cnt = 0;
  for(var i = 0; i < window.localStorage.length; i++)
  {
    var key = window.localStorage.key(i); // we get the key
    var value = window.localStorage.getItem(key); // get value, ruby: hh[key] = value

    if(key.indexOf('product_') == 0)
   {

    cnt = cnt + value*1;


   }
}
return cnt;
}
Add cart_get_number_of_items