var num1 = -1;
var num2 = -1;
var randNum = 0;

function genNum1()
{
	do
	{
    	randNum = Math.round(Math.random()*25);
   		randNum = randNum+1;
   	}
   	while ((randNum == num1) || (randNum == num2))
   	num1 = randNum; 
}

function genNum2()
{
	do
	{
    	randNum = Math.round(Math.random()*16);
   		randNum = randNum+1;
   	}
   	while ((randNum == num1) || (randNum == num2))
   	num2 = randNum; 
}

function numToString(theNum)
{
	if (theNum < 10)
	{
		theNum = theNum.toString();
		theNum = "0" + theNum;
	}
	else
		theNum = theNum.toString();
		
	return theNum;
}

function setBannerLeft()
{
	genNum1();
	document.getElementById('banner1').src = "bg" + numToString(num1) + ".jpg";
	timerID = setTimeout('setBannerRight()',3000);
}

function setBannerRight()
{
	genNum2();
	document.getElementById('banner2').src = "bg" + numToString(num2) + ".jpg";
	timerID = setTimeout('setBannerLeft()',3000);
}

function setInitial()
{
	genNum1();
	genNum2();
	document.getElementById('banner1').src = "bg" + numToString(num1) + ".jpg";
	document.getElementById('banner2').src = "bg" + numToString(num2) + ".jpg";
	timerID = setTimeout('setBannerLeft()',3000);
}