var onImgs = new Array();
onImgs['mainnav1'] = new Image();
onImgs['mainnav2'] = new Image();
onImgs['mainnav3'] = new Image();
onImgs['mainnav4'] = new Image();
onImgs['mainnav5'] = new Image();
onImgs['mainnav6'] = new Image();

onImgs['mainnav1'].src = '/img/en/menu_top_05_on.jpg';
onImgs['mainnav2'].src = '/img/en/menu_top_06_on.jpg';
onImgs['mainnav3'].src = '/img/en/menu_top_07_on.jpg';
onImgs['mainnav4'].src = '/img/en/menu_top_08_on.jpg';
onImgs['mainnav5'].src = '/img/en/menu_top_09_on.jpg';
onImgs['mainnav6'].src = '/img/en/menu_top_10_on.jpg';

function imgOn(imgName){
  if (document.images){
    document.images[imgName].style.cursor = 'pointer';
    document.images[imgName].src = onImgs[imgName].src;
  }
}

var offImgs = new Array();
offImgs['mainnav1'] = new Image();
offImgs['mainnav2'] = new Image();
offImgs['mainnav3'] = new Image();
offImgs['mainnav4'] = new Image();
offImgs['mainnav5'] = new Image();
offImgs['mainnav6'] = new Image();

offImgs['mainnav1'].src = '/img/en/menu_top_05.jpg';
offImgs['mainnav2'].src = '/img/en/menu_top_06.jpg';
offImgs['mainnav3'].src = '/img/en/menu_top_07.jpg';
offImgs['mainnav4'].src = '/img/en/menu_top_08.jpg';
offImgs['mainnav5'].src = '/img/en/menu_top_09.jpg';
offImgs['mainnav6'].src = '/img/en/menu_top_10.jpg';

function imgOff(imgName){
  if (document.images){
    document.images[imgName].style.cursor = 'pointer';
    document.images[imgName].src = offImgs[imgName].src;
  }
}