ActionScript: The Definitive Guide

Text Field Properties

When the body of text in a text field spans more lines than can be accommodated by the physical viewable region of the field, extra lines of text are hidden. The extra lines, however, are still part of the text field. To view those lines, we can click in the field and press the down arrow key until the excess lines appear. Obviously, we can’t expect users to use the arrow keys to scroll through text in a text field. Instead, we should provide buttons that scroll the text using the scroll and maxscroll properties, both of which use an index number to refer to the lines in a text field. The top line is number 1, and line numbers increase for every line in the text field, including those that exceed the viewable boundaries of the field. Figure 18.2 shows a sample text field’s line index values.

Figure 18-2. Text field line indexes

The scroll Property

The scroll property represents the line number of the topmost line currently displayed in a text field and can be accessed using textFieldName .scroll.

When a text field contains more lines than it can display at once, we can change which lines are shown in the field’s viewable region by setting the scroll property. For example, if we were to set the scroll property of the text field shown in Figure 18.2 to 3, the text field would display:

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The maxscroll Property

The maxscroll property tells us how far a ...