var currentdate = 0;
var core = 0;

function initArray() {

this.length = initArray.arguments.length;
  for (var i = 0; i < this.length; i++) {
  this[i] = initArray.arguments[i];
  }
}

link = new initArray(
"http://www.entercity.gr/",
"http://www.radio972.gr/diafhmisteite.html",
"http://www.cawg-greece.com/",
"http://www.idsnet.gr/"
);

image = new initArray(
"http://www.radio972.gr/banners/entercity.jpg",
"http://www.radio972.gr/banners/diafhmisteite.jpg",
"http://www.radio972.gr/banners/cawg-greece.jpg",
"http://www.radio972.gr/banners/idsnet.gif"
);

text = new initArray(
"Entercity.gr - Portal of Crete",
"Διαφημιστείτε Εδώ - Χώρος για Διαφήμιση",
"Cretan Animal Welfare Group (CAWG)",
"Internet Development Solutions"
);

var currentdate = new Date();
var core = currentdate.getSeconds() % image.length;
var ranlink  = link[core];
var ranimage = image[core];
var rantext  = text[core];

document.write('<a href=\"' +ranlink+ '\" target=\"_blank\"><img src=\"'+ranimage+'\" border="0" alt=\"'+rantext+'\"></a>');