# Add a digital catalog product with auto-applied order promotion

## Overview

Use the **order promotions** object to add a digital catalog product with auto-applied order promotion (for PSP business model).

## Use case

1. Add an HTML link or button to your page like the one below.
2. Create a JavaScript click handler to execute the InLine Client desired methods.
3. Use the TwoCoInlineCart.products.add({code, quantity, options}) method to prepare your catalog product.
4. Use the TwoCoInlineCart.cart.checkout() method to show the cart on your page.

## Sample request

### HTML

```html
<a href="#" class="btn btn-success" id="buy-button">Buy now!</a>
```

### JavaScript

```javascript
window.document.getElementById('buy-button').addEventListener('click', function() {
  TwoCoInlineCart.products.removeAll();
  TwoCoInlineCart.products.add({
    code: "STD_SUB",
    quantity: 3
  });

  TwoCoInlineCart.cart.checkout();
});
```

## Demo

After adding a digital catalog product with auto-applied order promotion using the above method, your cart should look like this:

{% embed url="<https://codepen.io/2checkout-documentation/pen/XWpzboV>" %}


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