//ͼƬÂÖ²¥ 400*60
var how_many_ads = 3;
var now = new Date()
var sec = now.getSeconds()
var ad = sec % how_many_ads;
ad +=1;
if (ad==1) {
document.write("<img src=/adimg/ad_400x60.gif width=400 height=60>");
}
if (ad==2) {
document.write("<img src=/adimg/ad_400.gif width=400 height=60>");
}
if (ad==3) {
document.write("<img src=/adimg/ad_400x60.gif width=400 height=60>");
}