Blocking requests

      var output = document.getElementById("output");

      while (true) {

        var feed = Ajax.requestJSONP(
                    "http://www.flickr.com/services/feeds/photos_public.gne",
                    { format: "json" }, "jsoncallback");

        for (var i=0; i<feed.items.length; ++i) {
          var img = document.createElement("img");
          img.src = feed.items[i].media.m;
          img.height = 80;
          output.appendChild(img);
        }

        hold(5000);

        while(output.firstChild)
          output.removeChild(output.firstChild);
      }

• Again, no callback needed. Browser stays responsive during request.