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# Method name:

siteEcom.onCartChange(handler: onCartChangeHandler)

# Method Link:

https://dev.wix.com/docs/sdk/frontend-modules/ecom/on-cart-change.md

# Method Description:

Triggered when a cart changes.

Triggered when:
+ A cart is modified by native UI elements such as the 'Add to Cart' button, increase (+) and decrease (-) item quantity buttons, remove line item button (x), etc.
+ The `refreshCart()` method is called.

> **Note:** Actions performed by any method other than `refreshCart()` don't trigger `onCartChange()`.

# Method Permissions:



# Method Permissions Scopes IDs:

undefined



# Method Code Examples:

## Add an event handler for cart changes

```javascript
import { ecom } from "@wix/site-ecom";
import { retrieveCartDetails } from 'backend/cartDetails';

// Handler function that gets the ID of the current cart on cart change
const handler = async () => {
    // retrieveCartDetails() is defined by you in a backend file
    // that calls currentCart.getCurrentCart from the
    // backend ecom SDK module.
    try {
        const cart = await retrieveCartDetails();
        let cartId = cart._id;
        console.log('Cart ID: ', cartId);
    } catch (error) {
        console.error(error);
        // Handle the error
    }
};

ecom.onCartChange(handler);
```