i = 3 // Number of banners that you have

banner1= new Image();
banner1.src = "/images/screen-gsbl1.jpg";
banner2 = new Image();
banner2.src = "/images/screen-gsbl2.jpg";
banner3 = new Image();
banner3.src = "/images/screen-gsbl3.jpg";


function randombanner(){
	var randomnumber = Math.random();
	i = Math.round( (i - 1) * randomnumber) + 1;
	document.banner.src = eval("banner" + i + ".src");
}

function startTime(){

        var time= new Date();
        hours= time.getHours();
        mins= time.getMinutes();
        secs= time.getSeconds();
        closeTime=hours*3600+mins*60+secs;
        closeTime+=5;  // How many seconds til the next rotation
        Timer();

}

function Timer(){
        var time= new Date();
        hours= time.getHours();
        mins= time.getMinutes();
        secs= time.getSeconds();
        curTime=hours*3600+mins*60+secs
        if (curTime>=closeTime){
                if (i < 3){	// The number 6 is the amount of banners that you have
                        i++;
                        document.banner.src = eval("banner" + i + ".src");
                }
                else{
                        i = 1;
                        document.banner.src = eval("banner" + i + ".src");
                }
                startTime();
        }
        else{
                window.setTimeout("Timer()",100)}

}
onload=startTime;