Health Bar Help

I found this script on the Unity Page and wanted to know how to convert it to work with a player's health is 100 instead of 1? If I try to change the playerEnergy as is, it will only work once it reaches 1 again.

Also, how can I set it to fill up with a timer for super attacks in a fighting game?

/* Using multiple Groups to clip the displayed Contents */

var bgImage : Texture2D; // background image that is 256 x 32
var fgImage : Texture2D; // foreground image that is 256 x 32
var playerEnergy = 1.0; // a float between 0.0 and 1.0

function OnGUI () {
    // Create one Group to contain both images
    // Adjust the first 2 coordinates to place it somewhere else on-screen
    GUI.BeginGroup (Rect (0,0,256,32));

    // Draw the background image
    GUI.Box (Rect (0,0,256,32), bgImage);

    // Create a second Group which will be clipped
    // We want to clip the image and not scale it, which is why we need the second Group
    GUI.BeginGroup (Rect (0,0,playerEnergy * 256, 32));

    // Draw the foreground image
    GUI.Box (Rect (0,0,256,32), fgImage);

    // End both Groups
    GUI.EndGroup ();
    GUI.EndGroup ();
}

In almost all cases it's easier to use values between 0.0 and 1.0 . But if you really want to change it to 0.0 to 100.0 just devide it by 100

GUI.BeginGroup (Rect (0,0,(playerEnergy / 100) * 256, 32));

or you can even precalculate it and use

GUI.BeginGroup (Rect (0,0,playerEnergy * 2.56, 32));