if (document.images) {
    img1on=new Image();
    img1on.src="images/b-jap2.gif";
    img1off=new Image();
    img1off.src="images/b-jap1.gif";

    img2on=new Image();
    img2on.src="images/b-nou2.gif";
    img2off=new Image();
    img2off.src="images/b-nou1.gif";

    img3on=new Image();
    img3on.src="images/b-nont2.gif";
    img3off=new Image();
    img3off.src="images/b-nont1.gif";

    img4on=new Image();
    img4on.src="images/b-prof2.gif";
    img4off=new Image();
    img4off.src="images/b-prof1.gif";

    img5on=new Image();
    img5on.src="images/b-book2.gif";
    img5off=new Image();
    img5off.src="images/b-book1.gif";

    img6on=new Image();
    img6on.src="images/b-rak2.gif";
    img6off=new Image();
    img6off.src="images/b-rak1.gif";

    img7on=new Image();
    img7on.src="images/b-wnew2.gif";
    img7off=new Image();
    img7off.src="images/b-wnew1.gif";

    img8on=new Image();
    img8on.src="images/b-wrd2.gif";
    img8off=new Image();
    img8off.src="images/b-wrd1.gif";

    img9on=new Image();
    img9on.src="images/b-shiso2.gif";
    img9off=new Image();
    img9off.src="images/b-shiso1.gif";

    img10on=new Image();
    img10on.src="images/b-ange2.gif";
    img10off=new Image();
    img10off.src="images/b-ange1.gif";

    img11on=new Image();
    img11on.src="images/b-samayoe2.gif";
    img11off=new Image();
    img11off.src="images/b-samayoe1.gif";

    img12on=new Image();
    img12on.src="images/b-jshigo2.gif";
    img12off=new Image();
    img12off.src="images/b-jshigo1.gif";

}

function imgOn(imgName) {
    if (document.images) {
        document[imgName].src=eval(imgName + "on.src");
    }
}

function imgOff(imgName) {
    if (document.images) {
        document[imgName].src=eval(imgName + "off.src");
    }
}