# RequestApplicationFieldCallback Function

> Callback function for requests expecting an ApplicationField value.

- **Product:** DS Server
- **Section:** Reference
- **Kind:** Function
- **Path:** DS Server > Reference > JavaScript API > RequestApplicationFieldCallback Function
- **290 words**
- **Web URL:** https://docs.textcontrol.com/ds-server/reference/javascript/requestapplicationfieldcallback/
- **LLMs URL:** https://docs.textcontrol.com/ds-server/reference/javascript/requestapplicationfieldcallback/llms.txt
- **LLMs-Full URL:** https://docs.textcontrol.com/ds-server/reference/javascript/requestapplicationfieldcallback/llms-full.txt

---

### Description

Callback function for requests expecting an [ApplicationField](https://docs.textcontrol.com/ds-server/reference/javascript/applicationfield/llms-full.txt) value.

### Syntax

```javascript
function(<ApplicationField> field)
```

### Examples

The following example demonstrates `RequestApplicationFieldCallback` in a practical document-editing workflow. Callback function for requests expecting an ApplicationField value.

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

function requestApplicationFieldCallback(field) {
    console.log("field:", field);
}

TXTextControl.textParts.getMainText(function(mainText) {
    const applicationFields = mainText.applicationFields;
    applicationFields.getItem(requestApplicationFieldCallback, onTxError);
}, onTxError);
```

---

## Nearby

- **Previous:** [RequestActivationStateCallback Function](https://docs.textcontrol.com/ds-server/reference/javascript/requestactivationstatecallback/llms-full.txt)
- **Next:** [RequestAutoBaselineCallback Function](https://docs.textcontrol.com/ds-server/reference/javascript/requestautobaselinecallback/llms-full.txt)