> For the complete documentation index, see [llms.txt](https://archive-docs.klaytn.foundation/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://archive-docs.klaytn.foundation/content/dapp/sdk/caver-js/v1.4.1/api-references/caver.klay/transaction/sendtx_legacy.md).

# Legacy

## sendTransaction (Legacy) <a href="#sendtransaction-legacy" id="sendtransaction-legacy"></a>

```javascript
caver.klay.sendTransaction(transactionObject [, callback])
```

Sends a transaction to the network.

Note: Only the account having `AccountKeyLegacy` can send this transaction.

**Parameters**

The parameters of sendTransaction are a transaction object and a callback function.

| Name              | Type     | Description                                                                                                |
| ----------------- | -------- | ---------------------------------------------------------------------------------------------------------- |
| transactionObject | Object   | The transaction object to send.                                                                            |
| callback          | Function | (optional) Optional callback, returns an error object as the first parameter and the result as the second. |

A transaction object of type `LEGACY` has the following structure:

| Name     | Type                                | Description                                                                                                                                                                                                                       |
| -------- | ----------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| from     | String                              | Address of this transaction sender.                                                                                                                                                                                               |
| to       | String                              | (optional) The destination address of the message, left undefined for a contract-creation transaction.                                                                                                                            |
| value    | Number \| String \| BN \| BigNumber | (optional) The value transferred for the transaction in peb, also the endowment if it's a contract-creation transaction.                                                                                                          |
| gas      | Number                              | The maximum amount of gas willing to pay for the transaction (unused gas is refunded).                                                                                                                                            |
| gasPrice | Number                              | (optional) Gas price provided by the sender in peb. The gasPrice must be the same as the unitPrice set in the Klaytn node.                                                                                                        |
| data     | String                              | (optional) Either an [ABI byte string](http://solidity.readthedocs.io/en/latest/abi-spec.html) containing the data of the function call on a contract, or in the case of a contract-creation transaction the initialization code. |
| nonce    | Number                              | (optional) Integer of a nonce. If omitted, it will be set by caver-js via calling `caver.klay.getTransactionCount`.                                                                                                               |

**Return Value**

The `callback` will return the 32-byte transaction hash.

`PromiEvent`: A promise combined event emitter. Will be resolved when the transaction receipt is available. Additionally the following events are available:

* `"transactionHash"` returns `String`: Is fired right after the transaction is sent and a transaction hash is available.
* `"receipt"` returns `Object`: Is fired when the transaction receipt is available.
* `"error"` returns `Error`: Is fired if an error occurs during sending. On an out-of-gas error, the second parameter is the receipt.

**Example**

```javascript
const account = caver.klay.accounts.wallet.add('0x{private key}')

var code = "0x603d80600c6000396000f3007c01000000000000000000000000000000000000000000000000000000006000350463c6888fa18114602d57005b6007600435028060005260206000f3";

// using the callback
caver.klay.sendTransaction({
    from: account.address,
    data: code // deploying a contracrt
}, function(error, hash){
    ...
});

// using the promise
caver.klay.sendTransaction({
    from: account.address,
    to: '0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe',
    value: '1000000000000000'
})
.then(function(receipt){
    ...
});

// using the event emitter
caver.klay.sendTransaction({
    from: account.address,
    to: '0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe',
    value: '1000000000000000'
})
.on('transactionHash', function(hash){
    ...
})
.on('receipt', function(receipt){
    ...
})
.on('error', console.error); // If an out-of-gas error, the second parameter is the receipt.
```