var rnd_urls = new Array(
'cn.pswnet.com',
'cn.pswnet.com',
'cn.pswnet.com',
'cn.pswnet.com',
'cn.pswnet.com',
'cn.pswnet.com',
'cn.pswnet.com');
   var rnd_img = new Array (
'immagini/header/h1.jpg', 
'immagini/header/h2.jpg',
'immagini/header/h3.jpg', 
'immagini/header/h4.jpg',
'immagini/header/h5.jpg', 
'immagini/header/h6.jpg',
'immagini/header/h7.jpg');   
var j = parseInt(Math.random()*rnd_urls.length);
   document.write('<a href="http://'+rnd_urls[j]+'"><img src="'+rnd_img[j]+'" width="650" height= "120" border="0" /></a>');