expand_region.js

import Sony.Vegas;

var one_second = Timecode.FromMilliseconds(1000);
var transport  = Vegas.Transport;
var start  = transport.LoopRegionStart;
var length = transport.LoopRegionLength;

transport.LoopRegionLength = length + one_second + one_second;
transport.LoopRegionStart = start - one_second;