var poweringButtonOn        = new Image();
var poweringButtonOff       = new Image();
var workingButtonOn         = new Image();
var workingButtonOff        = new Image();
var servicesButtonOn        = new Image();
var servicesButtonOff       = new Image();
var innovationButtonOn      = new Image();
var innovationButtonOff     = new Image();
var newsButtonOn            = new Image();
var newsButtonOff           = new Image();
var contactButtonOn         = new Image();
var contactButtonOff        = new Image();
//var careersButtonOn         = new Image();
//var careersButtonOff        = new Image();
var homeButtonOn            = new Image();
var homeButtonOff           = new Image();

function preloadMainMenu( imageDir )
{
  poweringButtonOn.src      = imageDir + "nav_powering_on.gif";
  poweringButtonOff.src     = imageDir + "nav_powering_off.gif";
  workingButtonOn.src       = imageDir + "nav_working_on.gif";
  workingButtonOff.src      = imageDir + "nav_working_off.gif";
  servicesButtonOn.src      = imageDir + "nav_services_on.gif";
  servicesButtonOff.src     = imageDir + "nav_services_off.gif";
  innovationButtonOn.src    = imageDir + "nav_innovation_on.gif";
  innovationButtonOff.src   = imageDir + "nav_innovation_off.gif";
  newsButtonOn.src          = imageDir + "nav_news_on.gif";
  newsButtonOff.src         = imageDir + "nav_news_off.gif";
  contactButtonOn.src       = imageDir + "nav_contacts_on.gif";
  contactButtonOff.src      = imageDir + "nav_contacts_off.gif";
  //careersButtonOn.src       = imageDir + "nav_careers_on.gif";
  //careersButtonOff.src      = imageDir + "nav_careers_off.gif";
  homeButtonOn.src          = imageDir + "nav_home_on.gif";
  homeButtonOff.src         = imageDir + "nav_home_off.gif";
}