# button

> A value that indicates which mouse button was pressed or released (if any) to cause this event: 0 is the left button, 1 is the right button, 2 is the middle button. A negative value indicates that no mouse button changed state during this event.

## Definition

* **Type:** Property
* **Namespace:** [UnityEngine.UIElements](/engine/6000.0/script-reference/unityengine/uielements.md)
* **Assembly:** UnityEngine.UIElementsModule

```csharp
public int button { get; protected set; }
```