// Pre-Load /images
  hardware = new Image();
  hardware.src = "/images/buttons/side/hardware.jpg";
  software = new Image();
  software.src = "/images/buttons/side/software.jpg";
  environment = new Image();
  environment.src = "/images/buttons/side/environment.jpg";

  hardware_off = new Image();
  hardware_off.src = "/images/buttons/side/hardware_off.jpg";
  software_off = new Image();
  software_off.src = "/images/buttons/side/software_off.jpg";
  environment_off = new Image();
  environment_off.src = "/images/buttons/side/environment_off.jpg";