# Boolean (function)

#### Availability

Flash Player 5.

#### Usage

    Boolean(expression)

#### Parameters

`expression` An expression to convert to a Boolean value.

#### Returns

A Boolean value or the value `expression`, as described below.

#### Description

Function; converts the parameter `expression` to a Boolean value and returns a value as follows:

- If `expression` is a Boolean value, the return value is `expression`.
- If `expression` is a number, the return value is `true` if the number is not zero, otherwise the return value is `false`.
- If `expression` is a string, the `toNumber` method is called and the return value is `true` if the number is not zero, otherwise the return value is `false`.
- If `expression` is undefined, the return value is `false`.
- If `expression` is a movie clip or an object, the return value is `true`.