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)); 
//please adjust the number here, the number "3" mean three pieces.

if(myNum == 1) document.write("<img src='img/banner1.jpg'>"); 
if(myNum == 2) document.write("<img src='img/banner2.jpg'>"); 
if(myNum == 3) document.write("<img src='img/banner.jpg'>");

//Add or Remove above sentences up to the pieces of BANNER. Something behind “src�is the  save location of BANNER.

    else {
document.write();
}
};
document.write("</CENTER>");