var theImages = new Array();

theImages[0] = "<a href = 'http://www.k-9kingdom.com' target='blank'><img src = 'images/web_components/ad-image1_k9Kingdom.jpg' border = '0'>";
theImages[1] = "<a href = 'http://www.royalcrestanimalspa.com' target='blank'><img src = 'images/web_components/ad-image1_royalcrest.jpg' border = '0'>";
theImages[2] = "<a href = 'http://www.sangrida.com' target='blank'><img src = 'images/web_components/ad-image1_sangrida.jpg' border = '0'>";
theImages[3] = "<a href = 'http://www.centralhtg.com' target='blank'><img src = 'images/web_components/ad-image1_heatingcooling.jpg' border = '0'>"

now=new Date()
num=(now.getSeconds())%4
document.write(theImages[num]);