# Button.onSetFocus

#### Availability

Flash Player 6.

#### Usage

    my_btn.onSetFocus = function(oldFocus){
    statements;
    };

#### Parameters

`oldFocus` The object to lose keyboard focus.

#### Returns

Nothing.

#### Description

Event handler; invoked when a button receives keyboard focus. The `oldFocus` parameter is the object that loses the focus. For example, if the user presses the Tab key to move the input focus from a text field to a button, `oldFocus` contains the text field instance.

If there is no previously focused object, `oldFocus` contains a `null` value.