var bannerImage = new Array();
bannerImage[0] = "banner1.jpg";
bannerImage[1] = "banner2.jpg";
bannerImage[2] = "banner3.jpg";
bannerImage[3] = "banner4.jpg";

var newBanner = 0;
var totalBanner = bannerImage.length;

function rotateBanner() 
{
	newBanner++;
	
  	if (newBanner == totalBanner) 
  	{
    	newBanner = 0;
  	}
  	
	document.getElementById('banner_img').src="./images/"+bannerImage[newBanner];
	
	// set the time below for length of image display
	// i.e., "4*1000" is 4 seconds
	setTimeout("rotateBanner()", 4*1000);
}