Formula (Extended): $ISBLANK Function
## Overview
Return true if the argument is blank.
## Syntax
```
$ISBLANK(String)
```
## Parameters
|Parameter|Type|Required|Description|
|:---|:---|:---|:---|
|String|Arbitrary String|Required||
### Column Usable as Parameters
|Parameter|Classification|Numerical Value|Date|Description|Check|
|:---|:---|:---|:---|:---|:---|
|String|Yes|Yes|Yes|Yes|Yes*1|
*1: Always false
## Return Value
True if blank. Otherwise, false.
### Return Value for Target Column
|Target|Return Value|
|:---|:---|
|Classification (including title, status, manager, owner)|Display the string "True" or "False"|
|Numerical Value (including work volume, progression rate, remaining work volume)|Do not display|
|Date (including start and completion)|Do not display|
|Description (including content)|Display the string "True" or "False"|
|Check (including lock)|Check ON if true, check OFF if false|
## Usage Example ①
Specify parameters by screen column name (name displayed)
### Formula
![image](https://pleasanter.org/binaries/968205418b83462886c090ca1066f6e8)
### Parameters
![image](https://pleasanter.org/binaries/21f1674f40434e9f8925cc81755dfbc7)
### Calculation Result
![image](https://pleasanter.org/binaries/e178dd24b6ce45cc943e042bf0bd0caa)