var how_many_ads = 12;
var now = new Date()
var sec = now.getSeconds()
var ad = sec % how_many_ads;
ad +=1;

if (ad==1) {
banner="cnjy_g_t01.jpg";
}

if (ad==2) {
banner="cnjy_g_t02.jpg";
}

if (ad==3) {
banner="cnjy_g_t03.jpg";
}

if (ad==4) {
banner="cnjy_g_t04.jpg";
}

if (ad==5) {
banner="cnjy_g_t05.jpg";
}

if (ad==6) {
banner="cnjy_g_t06.jpg";
}

if (ad==7) {
banner="cnjy_g_t07.jpg";
}

if (ad==8) {
banner="cnjy_g_t08.jpg";
}

if (ad==9) {
banner="cnjy_g_t09.jpg";
}

if (ad==10) {
banner="cnjy_g_t10.jpg";
}

if (ad==11) {
banner="cnjy_g_t11.jpg";
}

if (ad==12) {
banner="cnjy_g_t12.jpg";
}

document.write('<img src=\"' + banner + '\" width=635 height=16 ')