// vgl. http://code.google.com/p/rndpic/

function loadNewImage() {
  xmlhttp = new XMLHttpRequest();
  xmlhttp.onreadystatechange = function() {
    if (xmlhttp.readyState == 4) {
      var image = eval("(" + xmlhttp.responseText + ")");

      function switchImage() {
        var linkTag = document.getElementById("rndpic_link");
        var imageTag = document.getElementById("rndpic_image");
        //linkTag.href = image.target_url;
        var currentTime = new Date()
        var year = currentTime.getFullYear()
        linkTag.href = "index.php5?p=galerie&year="+year;
        imageTag.width = image.width;
        imageTag.height = image.height;
        imageTag.src = image.thumbnail_url;
      }

      var preloadedThumbnail = new Image();
      preloadedThumbnail.src = image.thumbnail_url;
      preloadedThumbnail.onload = switchImage

      // reload every 8 seconds
      window.setTimeout("loadNewImage()", 8 * 1000);
    }
  };
  xmlhttp.open("GET", "http://rndpic.appspot.com/json/trianhas?size=150u", true);
  xmlhttp.send();
}