var ver4 = (navigator.appVersion.charAt(0) == "4");
var NN4  = ver4 && (navigator.appName == "Netscape");
var IE4 = ver4 && (navigator.appName.charAt(0) == "M");
var NN3 = ((navigator.appVersion.charAt(0) == "3") && (navigator.appName == "Netscape"));

if(NN3 || NN4 || IE4){
        var imgB = new Array();
        imgB[0] = new Image();  imgB[0].src = "http://www.jmca.or.jp/img/menu/ball_1.gif";
        imgB[1] = new Image();  imgB[1].src = "http://www.jmca.or.jp/img/menu/ball_2.gif";
}

function Bin(nam,num) {
        if(NN3 || NN4 || IE4) document.images[nam].src = imgB[num].src;
}

function Bout(nam,num) {
        if(NN3 || NN4 || IE4) document.images[nam].src = imgB[num].src;
}