function $(id) {
  return document.getElementById(id);
}

function o$(id) {
  return opener.document.getElementById(id);
}

function dw(str) {
  document.write(str);
}

function a(str) {
  alert(str);
}

var myWindow;
function openCenteredWindow(url, name, width, height) {
  var left = parseInt((screen.availWidth/2) - (width/2));
  var top = parseInt((screen.availHeight/2) - (height/2));
  var windowFeatures = "width=" + width + 
                       ",height=" + height + 
                       ",resizable=1,location=0,status=0,menubar=0," + 
                       ",left=" + left + 
                       ",top=" + top + 
                       ",screenX=" + left + 
                       ",screenY=" + top;
  myWindow = window.open(url, name, windowFeatures);
  myWindow.resizeTo(width, height);
  myWindow.focus();
}