Adobe Extending Flash Professional CS4 - Manual (Page 413)

391 EXTENDING FLASH CS4 PROFESSIONAL
Shape object
Description
Read-only property; an array of Vertex objects (see
Vertex object ).
Example
The following example stores the first selected object in the
someShape variable, and then shows the number of vertices
for that object in the Output panel:
var someShape = fl.getDocumentDOM().selection[0];
fl.trace("The shape has " + someShape.vertices.length + " vertices.");