mcChris

here's the link code i'm using: Add to Cart it's very weird and hard to explain...the two browsers (ff & chrome) were seemingly refreshing the page when i clicked the link, thus adding another product in the page transition, giving me 1 product in the cart and 2 in the source code... ie6 doesn't do this...and i've been conditioned to believe if ie6 gets something right, it's really wrong... i also put the project code on my server, only changing the '<?=' to '<?php echo' and got the same weird browser behavior...and, i've been over the code several times and can't see an error anywhere... so i gave up and used the button...and it works...i don't know why...

wahoo!...i've finally fixed this by using a button with addToCart.php as the action: but i have no idea why it works and the link doesn't...

i uploaded my 'magic cart' to my web server for further testing and ran into this 'headers already sent' issue myself... after following falkencreative's solutions the issue didn't resolve...then i found this: http://www.phpbuilder.com/board/showthread.php?t=10310794 ...post #8 was what caused my headers to be sent...there are other ideas there too...

i'm still a bit new to php, but i've heard that 'headers already sent' is usually a white space problem...try putting 'session_start();' on the same line as '/** FUNCTIONS **/' and return directly after the slash...

to further complicate things, the problem behavior occurs in both firefox 3.0 and google chrome; but in ie6 (i'm sorry), the shopping cart code performs perfectly, as expected...i can add an item, go back and add more, etc and the source codes is correct... ???

Update: my shopping cart is 'magical' ...this situation is truly bizarre! after staring at this code for another day, i've noticed that when i click on the 'addToCart' link, the addToCart page displays 1 item in the quantity with the correct amount, shipping, and total; however, on viewing the source code i see this: > </pre> <table>Product IDQuantityAmountTULIPCHOC3$74.97Shipping:$32.97Total:$107.94</table> it's good math, but not a practical application ...thoughts?

from ShoppingCart.php: <?php class ShoppingCart { protected $items = array(); public function AddItem($product_id) { if(array_key_exists($product_id, $this->items)) { $this->items[$product_id] = $this->items[$product_id] + 1; } else { $this->items[$product_id] = 1; } } public function GetItemCost($product_id) { $cost_string = get_item_cost($product_id); $cost_float = "$cost_string" + 0; return $cost_float * $this->GetItemQuantity($product_id); } public function GetItemShippingCost($product_id) { return $this->GetItemQuantity($product_id) * $this->getShippingCostFor(get_item_cost($product_id)); } private function getShippingCostFor($price) { if ($price < 10) { return 1.99; } elseif ($price < 50) { return 10.99; } else { return 34.99; } } public function GetItems() { return array_keys($this->items); } public function GetItemQuantity($product_id) { return intval($this->items[$product_id]); } public function EmptyCart() { $this->items = array(); } } ?> and functions.php: <?php // DEFINE GLOBALS define ('STORE_XML_FILE', '../catalog.xml'); // DEFINE REFERENCES require_once ('templates.php'); require_once ('../classes/ShoppingCart.php'); // FUNCTIONS session_start(); function get_xml_catalog() { return new SimpleXMLElement(file_get_contents(STORE_XML_FILE)); } function get_item_cost($product_id) { foreach(get_xml_catalog() as $product) { if ($product_id == $product->id) { return $product->price; } } throw new Exception('item not found: ' . $product_id); } function product_exists($product_id) { foreach(get_xml_catalog() as $product) { if ($product->id == $product_id) return true; } return false; } function get_shopping_cart() { if (!isset($_SESSION['cart'])){ return new ShoppingCart(); } else return unserialize($_SESSION['cart']); } function set_shopping_cart($cart) { $_SESSION['cart'] = serialize($cart); } ?>

i'm working my way thru the shopping cart tutorial...in video 7, 12:13 minutes in...i've just completed the code for $quantity: ><?php $product_id = $_REQUEST['id']; if (product_exists($product_id)) { $shopping_cart->AddItem($product_id); } ?> </pre> <table>Product IDQuantityAmount $product_id $quantity $ amount </table> <br><br><?php set_shopping_cart($shopping_cart);<br><br in the video, when he refreshes the page, the item quantity goes up 1 as expected...when i refresh my page, the item quantity goes up by 2 each time...not good... i've compared my code with the code base and don't see an error...in my first attempt, i continued on with the videos, hoping the issue would resolve, but it didn't...so, i scrapped that code and started again from scratch, with the same result...checked the code again and i'm still not seeing an error...any thoughts as to what might be the cause?