# RequestRulerBarScaleUnitCallback Function

> Callback function for requests expectiong a RulerBarScaleUnit value.

- **Product:** DS Server
- **Section:** Reference
- **Kind:** Function
- **Introduced:** 30.0
- **Path:** DS Server > Reference > JavaScript API > RequestRulerBarScaleUnitCallback Function
- **257 words**
- **Web URL:** https://docs.textcontrol.com/ds-server/reference/javascript/requestrulerbarscaleunitcallback/
- **LLMs URL:** https://docs.textcontrol.com/ds-server/reference/javascript/requestrulerbarscaleunitcallback/llms.txt
- **LLMs-Full URL:** https://docs.textcontrol.com/ds-server/reference/javascript/requestrulerbarscaleunitcallback/llms-full.txt

---

### Description

Callback function for requests expectiong a [RulerBarScaleUnit](https://docs.textcontrol.com/ds-server/reference/javascript/txtextcontrol/rulerbarscaleunit-enumeration/llms-full.txt) value.

### Syntax

```javascript
function(<RulerBarScaleUnit> scaleUnit)
```

### Examples

The following example demonstrates `RequestRulerBarScaleUnitCallback` in a practical document-editing workflow. Callback function for requests expectiong a RulerBarScaleUnit value.

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

function requestRulerBarScaleUnitCallback(scaleUnit) {
    console.log("scale unit:", scaleUnit);
}

TXTextControl.rulerBar.getScaleUnit(requestRulerBarScaleUnitCallback, onTxError);
```

---

## Nearby

- **Previous:** [RequestRulerBarFormulaModeCallback Function](https://docs.textcontrol.com/ds-server/reference/javascript/requestrulerbarformulamodecallback/llms-full.txt)
- **Next:** [RequestSectionBreakKindCallback Function](https://docs.textcontrol.com/ds-server/reference/javascript/requestsectionbreakkindcallback/llms-full.txt)