Sword Glow like in ghostfight

The attached image was take from the flash movie Ghost Fight by justsolo.

Ive been trying to figure out just how the sword glows were done, i know they were made in actionscript but not sure how it was coded.

Im making a flash swordfighting game and i would just love to incorporate this effect. Im not keen on creating graphic effects that look like this. A script would make my life much easier. If anyone can help, thank you so much!