var Popup = function() {
  this.win = null;
}
Popup.prototype = new Object();
Popup.prototype.open = function(params) {
  this.close();
  this.win = window.open(params.uri, (params.name?params.name:""), (params.features?params.features:"resizable=yes,scrollbars=no,menubar=no,toolbar=no,status=no,directories=no,location=no") + ",top=" + params.top + ",left=" + params.left + ",width=" + params.width + ",height=" + params.height);
  if (this.win.focus) this.win.focus();
  return this.win;
}
Popup.prototype.close = function() {
  if (this.win != null) {
    if (!this.win.closed && this.win.close) this.win.close();
    this.win = null;
  }
}