# Control Block

## Description

* Control blocks are used to distinguish standard HTML input elements from Sodium input elements in a [Form File](../program-structure/form-file).
* Control blocks cannot be nested.
* Sodium CSS rules only applies to input elements in Control Block and Data Block elements.
* Sodium event/triggers only applies to input elements in Control Block and Data Block elements.
* Control block's name is mandatory and must be unique in a form file.

## Declaration

```
<controlblock
    control-block-name  = "">
</controlblock>
```

## Properties

### &#x20;control-block-name property

&#x20;**Mandatory :** yes\
&#x20;**Unique :** yes\
&#x20;**Data Type :** char\
&#x20;**Default Value:** -\
&#x20;**Predefined Values Allowed:** -

## Triggers

None

## Allowed Inner HTML Elements

&#x20;Standard HTML Tags\
&#x20;[Inputs](inputs)\
&#x20;[Tree Element](tree-element)

## Built-in Functions
