var preloadFlag = false;

if (document.images)
{
  var onImgArray = new Array();
  onImgArray['home'] = new Image();
  onImgArray['about_us'] = new Image();
  onImgArray['activities'] = new Image();
  onImgArray['events'] = new Image();
  onImgArray['reports'] = new Image();
  onImgArray['business_centre'] = new Image();
  onImgArray['contact'] = new Image();
  onImgArray['gallery'] = new Image();
  onImgArray['home'].src = 'images/menu2/home_hover_en.png';
  onImgArray['about_us'].src = 'images/menu2/about_us_hover_en.png';
  onImgArray['activities'].src = 'images/menu2/activities_hover_en.png';
  onImgArray['events'].src = 'images/menu2/events_hover_en.png';
  onImgArray['reports'].src = 'images/menu2/reports_hover_en.png';
  onImgArray['business_centre'].src = 'images/menu2/business_centre_hover_en.png';
  onImgArray['contact'].src = 'images/menu2/contact_hover_en.png';
  onImgArray['gallery'].src = 'images/menu2/gallery_hover_en.png';

  var offImgArray = new Array();
  offImgArray['home'] = new Image();
  offImgArray['about_us'] = new Image();
  offImgArray['activities'] = new Image();
  offImgArray['events'] = new Image();
  offImgArray['reports'] = new Image();
  offImgArray['business_centre'] = new Image();
  offImgArray['contact'] = new Image();
  offImgArray['gallery'] = new Image();
  offImgArray['home'].src = 'images/menu2/home_en.png';
  offImgArray['about_us'].src = 'images/menu2/about_us_en.png';
  offImgArray['activities'].src = 'images/menu2/activities_en.png';
  offImgArray['events'].src = 'images/menu2/events_en.png';
  offImgArray['reports'].src = 'images/menu2/reports_en.png';
  offImgArray['business_centre'].src = 'images/menu2/business_centre_en.png';
  offImgArray['contact'].src = 'images/menu2/contact_en.png';
  offImgArray['gallery'].src = 'images/menu2/gallery_en.png';

  preloadFlag = true;
}

function imageOn(imgName)
{
    if (preloadFlag) {
        document.images[imgName].src = onImgArray[imgName].src;
    }
}

function imageOff(imgName)
{
    if (preloadFlag) {
        document.images[imgName].src = offImgArray[imgName].src;
    }
}