var cando = false;
var browserName = navigator.appName;
var browserVer = parseInt(navigator.appVersion);
if (browserName == "Netscape" && browserVer >= 3) cando = true;
else if( browserVer >=4 ) cando=true;
if( cando ) {
        imag = new Array();
        imag[0] = "images/air/mail.gif";
        imag[1] = "images/air/mails.gif";
        imag[2] = "images/air/home.gif";
        imag[3] = "images/air/homes.gif";
        imag[4] = "images/air/map.gif";
        imag[5] = "images/air/maps.gif";

        im = new Array()
        for (var i = 0; i < imag.length; i++){
                if( imag[i] != "" ) {
                        im[i] = new Image();
                        im[i].src = imag[i];
                }
        }
}

function swtch(num,imgname){
        if( cando )
        eval("document.getElementById('"+imgname+"').src = im[num].src;");
}