Actionscript Cookbook

8.14. Scrolling Text Programmatically

Problem

You want to scroll text in a text field via ActionScript without requiring user input.

Solution

Use the scroll, maxscroll, bottomScroll, hscroll, and maxhscroll properties of the text field.

Discussion

You can control the scrolling of a text field with ActionScript and without the aid of a scrollbar. For example, you may want to scroll the contents of a text field automatically to display a word or selection within the text. Or perhaps you don’t want to use the ScrollBar component for file size-optimization reasons. Regardless, you can programmatically control a text field’s scrolling in both the vertical and horizontal directions using some built-in properties. You should use the scroll, maxscroll, and bottomScroll properties to control vertical scrolling, and use the hscroll and maxhscroll properties to control horizontal scrolling.

Every text field has a number of lines, whether it is 1 or 100. Each of these lines is identified by a number starting at one. Some of these lines may be visible, and some may be beyond the border of the text field. Therefore, to view the lines that extend beyond the visible portion of the text field you must scroll to them. Figure 8-1 illustrates this point. It depicts a text field’s display, in which the solid line indicates the object’s border—the visible area—and the dotted line surrounds the rest of the text contained within the object but lying outside the its visible area. To the left of the ...