function PageBack() { history.back(); }

function VersionCheck(IEver,NNver)
{
    APPVER  = parseInt(navigator.appVersion);
    APPNAME = navigator.appName;

    if ((APPNAME.indexOf("Microsoft") != -1) && (APPVER >= IEver)) {
        return 1;
    }
    else if ((APPNAME.indexOf("Netscape") != -1) && (APPVER >= NNver)) {
        return 1;
    }
    else {
        return 0;
    }
}

function SP(IMGNAME,IMGPATH)
{
    if(VersionCheck(4,3)) document.images[IMGNAME].src = IMGPATH;
}

function PP(IMGNAME,IMGPATH)
{
    if (VersionCheck(4,3)) {
        IMGNAME     = new Image();
        IMGNAME.src = IMGPATH;
    }
}

PP('BTN01','./navi/guide_01.gif');
PP('BTN02','./navi/guide_02.gif');
PP('BTN03','./navi/guide_03.gif');