ActionScript for Flash MX: The Definitive Guide, 2nd Edition By Colin Moock
Chapter 18. ActionScript Language Reference
Button._xscale Property
Flash 6
width of a button, as a percentage
read/write
theButton._xscale
Description
The floating-point _xscale property specifies the width of theButton, relative to its original width, expressed as a percentage. Its "original width" is the pixel width of its Library symbol. When the current width of theButton is the same as its original width, _xscale is 100. An _xscale of 200 doubles theButton's original width; an _xscale of 50 halves its original width.
Button._xscale is directly analogous to MovieClip._xscale; see that property entry for full details.
Example
// Double run_btn's width, relative to its Library symbol's width run_btn._xscale = 200;