> For the complete documentation index, see [llms.txt](https://a2n-finance.gitbook.io/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://a2n-finance.gitbook.io/docs/developer/sdk/select-functions-to-use.md).

# Select functions to use

All functions are packed into **window\.a2n** object. 

#### Init Read Contract:

```
window.a2n.initReadContract()
```

Create an A2N smart contract instance to read/get data only. Methods of this instance do not require customers' wallet account permission.

#### Init Write Contract:

```
window.a2n.initWriteContract()
```

Developers can use this method to send transactions to A2N smart contract.

#### Get a product by ID from A2N Smart Contract:

```
window.a2n.getProductByIdFromSM(readContractInstance, productId)
```

To get a product and its subscription plans from A2N smart contract.

#### Get a product by ID from A2N cloud database:

```
window.a2n.getProductByIdFromDB(productId)
```

Get a product with additional information, such as description, image. and external link...

#### Get my subscribers:

```
window.a2n.getMySubscribers(readContractInstance, accountAddress)
```

Get all subscribers of an account address.

#### Get my subscriptions:

```
window.a2n.getMySubscriptions(readContractInstance, accountAddress)
```

Get all subscriptions of an account address.

#### Subscribe/purchase a subscription product:

```
widow.a2n.subscribe(writeContractInstance, productId, planId)
```

Send a transaction to A2N smart contract and complete a payment process.

#### Get current account:

```
window.a2n.getCurrenctAccount()
```

Get a customer's connected account on your website.

#### Insert a subscription product into your website:

```
widow.a2n.initDiv(subscriptionProductElementId)
```

Insert subscription product information into an HTML tag.

To see more details, you can check here: <https://github.com/a2nfinance/app/blob/master/sdk/index.js>