Adobe Extending Flash Professional CS4 - Manual (Page 317)

295 EXTENDING FLASH CS4 PROFESSIONAL
HalfEdge object
Description
Read-only property; an integer with a value of 0 or 1 that specifies the index for this HalfEdge object in the parent edge.
Example
The following example displays the index value for the specified half edge in the Output panel:
var shape = fl.getDocumentDOM().selection[0];
var hEdge = shape.edges[0].getHalfEdge(0);
var heIndex = hEdge.index;