# AddSubTextPartCallback Function

> Callback function for functions which add a subtextpart.

- **Product:** TX Text Control .NET Server
- **Section:** Reference
- **Kind:** Function
- **Path:** TX Text Control .NET Server > Reference > JavaScript API > AddSubTextPartCallback Function
- **333 words**
- **Web URL:** https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/javascript/addsubtextpartcallback/
- **LLMs URL:** https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/javascript/addsubtextpartcallback/llms.txt
- **LLMs-Full URL:** https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/javascript/addsubtextpartcallback/llms-full.txt

---

### Description

Callback function for functions which add a [subtextpart](https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/javascript/subtextpart/llms-full.txt).

### Syntax

```javascript
function(<SubTextPartCallbackData> response, <SubTextPartCollection.AddResult> addResult)
```

### Examples

The following example demonstrates `AddSubTextPartCallback` in a practical document-editing workflow. Callback function for functions which add a subtextpart.

```javascript
function onTxError(error) {
    console.error("TX Text Control error:", error.msg);
    error.handled = true;
}

function addSubTextPartCallback(response, addResult) {
    console.log("Callback values:", { response, addResult });
}

TXTextControl.textParts.getMainText(function(mainText) {
    const subTextParts = mainText.subTextParts;
    subTextParts.add("InvoiceAddress", 25, 1, 5, addSubTextPartCallback, onTxError);
}, onTxError);
```

---

## Nearby

- **Previous:** [AddFootnoteCallback Function](https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/javascript/addfootnotecallback/llms-full.txt)
- **Next:** [ApplicationField Object](https://docs.textcontrol.com/tx-text-control-dotnet-server/reference/javascript/applicationfield/llms-full.txt)