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"));

var imgS=new Array();

imgS[1]=new Image();imgS[1].src="top_img/menu_btn01_off.gif";
imgS[2]=new Image();imgS[2].src="top_img/menu_btn01_on.gif";
imgS[3]=new Image();imgS[3].src="top_img/menu_btn02_off.gif";
imgS[4]=new Image();imgS[4].src="top_img/menu_btn02_on.gif";
imgS[5]=new Image();imgS[5].src="top_img/menu_btn03_off.gif";
imgS[6]=new Image();imgS[6].src="top_img/menu_btn03_on.gif";
imgS[7]=new Image();imgS[7].src="top_img/menu_btn04_off.gif";
imgS[8]=new Image();imgS[8].src="top_img/menu_btn04_on.gif";
imgS[9]=new Image();imgS[9].src="top_img/menu_btn05_off.gif";
imgS[10]=new Image();imgS[10].src="top_img/menu_btn05_on.gif";
imgS[11]=new Image();imgS[11].src="top_img/menu_btn06_off.gif";
imgS[12]=new Image();imgS[12].src="top_img/menu_btn06_on.gif";
imgS[15]=new Image();imgS[15].src="top_img/menu_btn09_off.gif";
imgS[16]=new Image();imgS[16].src="top_img/menu_btn09_on.gif";

function swImg(num,posName) {
        if(NN3 || NN4 || IE4) posName.src = imgS[num].src;
}