var how_many_ads =4;
var now = new Date()
var sec = now.getSeconds()
var ad = sec % how_many_ads;
ad +=1;

if (ad==1) {
banner="http://www.cthy.com/4a/home/flash/Ad_cthy.swf";
width="960";
height="100";
}

if (ad==2) {
//banner="http://www.cthy.com/4a/home/flash/qingxin.swf";
banner="http://www.cthy.com/4a/home/flash/Ad_cthy.swf";
width="960";
height="100";
}

if (ad==3) {
//banner="http://www.cthy.com/4a/home/flash/hjjy.swf";
banner="http://www.cthy.com/4a/home/flash/Ad_cthy.swf";
width="960";
height="100";
}

if (ad==4) {
//banner="http://www.cthy.com/images/beichuantop.jpg";
banner="http://www.cthy.com/4a/home/flash/Ad_cthy.swf";
width="960";
height="100";
}
document.write('<object classid=\"clsid:D27CDB6E-AE6D-11cf-96B8-444553540000\" codebase=\"http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=6,0,29,0\" width=\"' + width + '\" height=\"' + height + '\">');
document.write('<param name=\"movie\" value=\"' + banner + '\">');
document.write('<param name=\"quality\" value=\"high\">'); 
document.write('<embed src=\"' + banner + '\" quality=\"high\" pluginspage=\"http://www.macromedia.com/go/getflashplayer\" type=\"application/x-shockwave-flash\" width=\"' + width + '\" height=\"' + height + '\">'); 
document.write('</object>');