Welcome to the OpenCart Test Page This is a simple page that can be used to test your installation of the OpenCart application software. You should print the source code for this page in order to understand how to use the shopping cart. In general, you will find that all of the documentation that applies to PayPal also applies to this application, so you can use it as a direct substitution for PayPal. Here is a sample link that demonstrates how the shopping cart can be used to purchase a product using a standard web link: Purchase A Green Widget   Another way to handle the purchase of an item is to use a form to handle the purchase. Here is an example of a form that is used to handle the purchase of a product: Purchase A Blue Widget Enter Quantity:   There are also several custom routines that can be used to break out the functionality into separate modules -- all of these modules are found in the distribution CGI directory, cgi-bin.   In general, the webscr CGI routine is the hook that makes OpenCart look like PayPal, however there are several other routines that can be invoked independently to allow you to customize the behavior of the shopping cart. Here are a few of those routines: add.pl is used to provide a standard (non-Paypal) hook into the OpenCart application. It accepts values for itemno, quantity, price, title, and other elements. You can read the source code for this module to see the elements it it referencing. Here is a way to buy something using add.pl instead of webscr (its PayPal equivalent):   Purchase A Red Widget     checkout.pl is used to start the checkout process after someone has put one or more items in their shopping cart. This routine is invoked directly from the shopping cart page, but can be invoked independently as a standalone routine. It requires no additional parameters.   clear.pl is used to clear an exiting shopping cart. Because the application can be configured to keep items in a shopping cart for several days, this routine can be used to remove everything from an existing shopping cart in a single click. This routine does not require any parameters.   display.pl is used to display (view) the contents of the current shopping cart. This feature can also be invoked using the webscr CGI routine with the parameter "display=1". If you use display.pl to view your shopping cart, you do not have to pass it any paramaters.   There are several other routines that are used to handle the checkout process, update item quzntities in an existing cart, and handle other internal functions. In most cases, the shopping cart handles this internally without any external intervention. The OpenCart application is so easy to implement that all you need to have are links to add.pl to add items to your shopping cart, and a link to display.pl to view the contents of the shopping cart. Buttons inside the shopping cart allow the user to invoke all of the other features built into the system automatically.