function delete_position(url, ask)
{
  if(confirm(ask))
  {
    location.href=url;
  }
  return false;
}
function click_button()
{
  document.getElementById('last').value = document.getElementById('last_id').value;
  return true;
}
function show_img(img,width,height)
{
  var a;
  var b;
  var url;
  vidWindowWidth=width;
  vidWindowHeight=height;
  a=(screen.height-vidWindowHeight)/5;
  b=(screen.width-vidWindowWidth)/2;
  features = "top=" + a + ",left=" + b + ",width=" + 
              vidWindowWidth + ",height=" + 
              vidWindowHeight + 
              ",toolbar=no,menubar=no,location=no,directories=no,scrollbars=no,resizable=no";
  url="show.php?img=" + img;
  window.open(url,'',features,true);
}