advimgs = new Array('arcsight.jpg', 'cyberoam.jpg', 'emc.jpg','mirapoint.JPG', 'symantec.jpg', 'vmware.jpg');
advimgidx = 0;

function nextAdvImg(){
if (document.getElementById("advertimg"))
    document.getElementById("advertimg").src = 'inevidenza/' + advimgs[(advimgidx++)%advimgs.length];
setTimeout("nextAdvImg();", 2000);
}

setTimeout("nextAdvImg();", 1000);