function refresh_img(url,interval) {
                       setTimeout(function() {
                          new_img = url+'?t=' + new Date().getTime()
                          document.getElementById('dynamic_img').src=new_img;
                          refresh_img(url,interval);
                       }, interval);
                  }
refresh_img("http://breda.gemeentedocumenten.nl/webcam/current.jpg",3000);