You do not need Javascript for a hex editor.
There is a description of the save editor in that topic. Basically, you run the save editor, click on the '...' button and browse to the saved game folder you wish to modify, and open the data.000 file. You can then edit the experience points, primary stats and skill points (I found adding unused skill points then loading the game and learning skills to be more reliable than trying to learn skills from within the save editor).
