JQuery :: Ajax Updating SQL Then Load To Bring It Back

I setup a jquery ajax request to update my sql database... (add a product to shopping cart) then after it completes I want to use .load to re-load the shoppingcart (the cart is currently loaded with php include - so it is it's own seperate .php file). The problem is that when it reloads it doesn't have the "current version" If i refresh the page it's fine..

Example -
<script type="text/javascript">
$(function() {
$("#addtocart").click(function() {
$.ajax({
url: "addtocart.php",
data: **form data here**,
complete: function() { $("#cart").load("cart.php"); }
});
});
});
</script>
<div id="cart">
<? include("cart.php"); ?>
</div>
<button id="addtocart">Add to cart</button>
--

I have also tried to put a variable in front from the $.ajax and then use $("#cart").ajaxComplete(function() { $(this).load("cart.php"); } });
But yet still no luck. How to make ajax load a page after the mysql update has been done then display it?! I used to do this all the time before I started using jquery. When readyState was = 4 { load page code here } it would always work.