function newImage(arg) {
  if (document.images) {
    rslt = new Image();
    rslt.src = arg;
    return rslt;
  }
}

function changeImages() {
  if (document.images && (preloadFlag == true)) {
    for (var i=0; i<changeImages.arguments.length; i+=2) {
      document[changeImages.arguments[i]].src = changeImages.arguments[i+1];
    }
  }
}

var preloadFlag = false;
function preloadImages() {
if (document.images) {
    m_intro_over = newImage("../images/m_intro_over.gif");
    m_school_over = newImage("../images/m_school_over.gif");
    m_subject_over = newImage("../images/m_subject_over.gif");
    m_kyoumu_over = newImage("../images/m_kyoumu_over.gif");
    m_gallery_over = newImage("../images/m_gallery_over.gif");
    m_faq_over = newImage("../images/m_faq_over.gif");
    m_gansyo_over = newImage("../images/m_gansyo_over.gif");
    m_data_claim_over = newImage("../images/m_data_claim_over.gif");
    m_opencollege_over = newImage("../images/m_opencollege_over.gif");
    m_guest_over = newImage("../images/m_guest_over.gif");
    m_support_over = newImage("../images/m_support_over.gif");
    m_link_over = newImage("../images/m_link_over.gif");
    preloadFlag = true;
  }
}