Prefix layer names

Hi, I'm not very good at java scripts so I was wondering if you could help.

I'd like to be able to select a bunch of layers in photoshop, and run a script that would prefix all the layers names with whatever I choose in the script.

I don't want any UI, I just want it to add the prefix and be done, no questions asked. I'll edit the script to modify the exact prefix text. It has to only affect selected layers OR the layers within a selected folder.

I know it's probably stupid simple.

Thanks in advance.

Ian