today=new Date(); 
jran=today.getTime(); 
function rnd() { 
ia=9301; 
ic=49297; 
im=233280; 
jran = (jran*ia+ic) % im; 
return jran/(im*1.0); 
}; 
function rand(number) { 
return Math.ceil(rnd()*number); 
}; 
document.write("<center>" ); 
for(i=1;i<=1;i++) { 
myNum=(rand(3)); //改成你要随机显示的图片数； 
if(myNum == 1) document.write("<a href=/air-jordan/><img src=/images2008/ad1.gif border=0></a>" ); 
if(myNum == 2) document.write("<a href=/air-jordan/><img src=/images2008/ad2.gif border=0></a>" ); 
if(myNum == 3) document.write("<a href=/ato/><img src=/images2008/ad3.gif border=0></a>" ); 

else { 
document.write() ; 
} 
};