> For the complete documentation index, see [llms.txt](https://tutorial.neoline.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://tutorial.neoline.io/reference/neo3-provider-api-legacy/common-events/block_height_changed.md).

# BLOCK\_HEIGHT\_CHANGED

On a BLOCK\_HEIGHT\_CHANGED event, the block has advanced to the next.

<table><thead><tr><th width="314">Parameter</th><th>Description</th></tr></thead><tbody><tr><td><code>chainId: number</code></td><td>ChainId is the type of wallet selection network</td></tr><tr><td><code>blockHeight: number</code></td><td>Height of the new block</td></tr><tr><td><code>blockTime: number</code></td><td>Timestamp of the new block</td></tr><tr><td><code>blockHash: string</code></td><td>Hash of the new block</td></tr><tr><td><code>tx: string[]</code></td><td>List of transaction ids executed in the new block</td></tr></tbody></table>

## Example

```js
neoline.addEventListener(neoline.EVENT.BLOCK_HEIGHT_CHANGED, (result) => {
    console.log('block height:', result);
});
/* Another */
window.addEventListener('NEOLine.NEO.EVENT.BLOCK_HEIGHT_CHANGED', (result) => {
    console.log('block height:', result.detail);
});
```


---

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