function SwitchPic(IMGNAME, IMGPATH)
{
    document.images[IMGNAME].src = IMGPATH;
}
function PreloadPic(IMGNAME, IMGPATH)
{
    IMGNAME     = new Image();
    IMGNAME.src = IMGPATH;
}


PreloadPic('ro_1', 'images/button/inter_on.gif');
PreloadPic('ro_2', 'images/button/sup_on.gif');
PreloadPic('ro_3', 'images/button/hp_on.gif');
PreloadPic('ro_4', 'images/button/mg_on.gif');
PreloadPic('ro_5', 'images/button/kiyaku_on.gif');
PreloadPic('ro_6', 'images/button/fl_on.gif');
PreloadPic('ro_7', 'images/button/bfl_on.gif');
PreloadPic('ro_8', 'images/button/hos_on.gif');
PreloadPic('ro_9', 'images/button/b_airh_on.gif');
PreloadPic('ro_10', 'images/button/b_freed_on.gif');