ActionScript: The Definitive Guide

Name

scroll Property — the current top line displayed in a text field

Availability

Flash 4 and later

Synopsis

textfield.scroll

Returns

A positive integer representing the number of the topmost viewable line of a text field.

Description

The scroll text field property can be both retrieved and set. When we retrieve the value of a text field’s scroll property, it indicates the number of the line currently displayed as the first line in the field’s viewable region. When we set the value of scroll, it scrolls the text field, making the supplied line number the top line in the field’s viewable region. The scroll property is normally used with maxscroll to create text-scrolling interfaces as described under Section 18.4.3 in Chapter 18.

Usage

Though scroll is listed as a function in Flash, it is effectively used as a property of a text field variable. Notice that parentheses are not used when scroll is invoked.

Bugs

In Build 5.0 r30 of the Flash Player, when a text field’s font is embedded, using scroll may cause some text to be displayed outside the visual region of the field. Some text may not be removed as the text in the field scrolls. To work around the problem, use a mask over the text field layer. This problem was fixed in Build 5.0 r41.

Example

// Sets x to the index of the top line displayed in myField
var x = myField.scroll;
// Scrolls the text in myField down one
myField.scroll++;

See Also

maxscroll; Section 18.4.1 in Chapter 18